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PHP-Cheat-Sheet.pdf

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This document provides a cheat sheet for beginners on PHP basics and functions. It includes sections on PHP syntax, variables, arrays, strings, operators, loops, conditional statements, forms, regular expressions, functions, filters, HTTP functions, MySQL, and dates. Key points covered are how to include PHP in files, write comments, output data, define variables and constants, work with arrays and strings, and use common functions related to variables, strings, arrays, and more. The cheat sheet serves as a quick reference guide for PHP basics, syntax, and core functions.

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Beginner’s Essential PHP CHEAT SHEET Fast, flexible and pragmatic scripting language.
Table of Contents PHP Basics 2 Variables and Constants 2 PHP Arrays - Grouped Values 7 PHP Strings 13 PHP Operators 21 Loops in PHP 23 Conditional Statements 23 Working with Forms in PHP 24 Regular Expressions 26 PHP Functions 28 PHP Filters 29 HTTP Functions in PHP 31 Working with MySQL 31 Date and Time 36 PHP Errors 40 WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​1
PHP BASICS Including PHP in a File <?php // place PHP code here ?> Writing Comments // Denotes comments that only span on one line # Another way of producing single-line comments /*...*/ Everything between /* and */ is not executed, also works across several lines Outputting Data <?php echo "<h1>PHP Cheat Sheet</h1>"; ?> Writing PHP Functions function NameOfTheFunction() { //place PHP code here } VARIABLES AND CONSTANTS Defining Variables <?php $BlogPostTitle = "PHP Cheat Sheet"; ?> WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​2
Types of Data Integers Integers are non-decimal numbers between -2,147,483,648 and 2,147,483,647. They must have at least one digit and no decimal point. Can be in decimal, hexadecimal or octal. Floats This is the name for numbers with a decimal point or in exponential form. Strings This simply means text, we will talk about it in detail further below. Boolean values Meaning true/false statements. Arrays Arrays are variables that store several values. We will talk about them in detail further below. Objects Objects store both data and information on how to process it. Resources These are references to functions and resources outside of PHP. NULL A variable that is NULL doesn’t have any value. Variable Scope function myFunction() { global $a, $b; $b = $a - $b; } WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​3
Predefined Variables $GLOBALS Used to access global variables from anywhere inside a PHP script​. $_SERVER Contains information about the locations of headers, paths and scripts. $_GET Can collect data that was sent in the URL or submitted in an HTML form. $_POST Used to gather data from an HTML form and to pass variables. $_REQUEST Also collects data after submitting an HTML form Variable-handling Functions boolval Used to retrieve the boolean value of a variable debug_zval_dump Outputs a string representation of an internal zend value empty Checks whether a variable is empty or not floatval Get the float value of a variable (doubleval is another possibility) get_defined_vars Returns an array of all defined variables get_resource_type Returns the resource type gettype Retrieves the variable type WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​4
import_request_variables Import GET/POST/Cookie variables into the global scope intval Find the integer value of a variable is_array Checks whether a variable is an array is_bool Finds out if a variable is a boolean​ of 538 is_callable Verify whether you can call the contents of a variable as a function is_countable Check whether the contents of a variable are countable is_float Find out if the type of a variable is float, alternatives: is_double and is_real is_int Check if the type of a variable is an integer, is_integer and is_long also works is_iterable Verify that a variable’s content is an iterable value is_null Checks whether a variable’s value is NULL is_numeric Find out if a variable is a number or a numeric string is_object Determines whether a variable is an object is_resource Check if a variable is a resource is_scalar Tests if a variable is a scalar WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​5
is_string Find out whether the type of a variable is a string isset Determine if a variable has been set and is not NULL print_r Provides human-readable information about a variable serialize Generates a representation of a value that is storable settype Sets a variable’s type strval Retrieves the string value of a variable unserialize Creates a PHP value from a stored representation unset Unsets a variable var_dump Dumps information about a variable var_export Outputs or returns a string representation of a variable that can be parsed Constants define(name, value, true/false) Aside from user-defined constants, there also a number of default PHP constants: __LINE__ Denotes the number of the current line in a file __FILE__ Is the full path and filename of the file WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​6
__DIR__ The directory of the file __FUNCTION__ Name of the function __CLASS__ Class name, includes the namespace it was declared in __TRAIT__ The trait name, also includes the namespace __METHOD__ The class method name __NAMESPACE__ Name of the current namespace PHP ARRAYS – GROUPED VALUES Indexed arrays Arrays that have a numeric index Associative arrays Arrays where the keys are named Multidimensional arrays Arrays that contain one or more other arrays Declaring an Array in PHP <?php $cms = array("WordPress", "Joomla", "Drupal"); echo "What is your favorite CMS? Is it " . $cms[0] . ", " . $cms[1] . " or " . $cms[2] . "?"; ?> Array Functions array_change_key_case Changes all keys in an array to uppercase or lowercase WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​7
array_chunk Splits an array into chunks array_column Retrieves the values from a single column in an array array_combine Merges the keys from one array and the values from another into a new array array_count_values Counts all values in an array array_diff Compares arrays, returns the difference (values only array_diff_assoc Compares arrays, returns the difference (values and keys) array_diff_key Compares arrays, returns the difference (keys only) array_diff_uassoc Compares arrays (keys and values) through a user callback function array_diff_ukey Compares arrays (keys only) through a user callback function array_fill Fills an array with values array_fill_keys Fills an array with values, specifying keys array_filter Filters the elements of an array via a callback function array_flip Exchanges all keys in an array with their associated values array_intersect Compare arrays and return their matches (values only) WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​8
array_intersect_assoc Compare arrays and return their matches (keys and values) array_intersect_key Compare arrays and return their matches (keys only) array_intersect_uassoc Compare arrays via a user-defined callback function (keys and values) array_intersect_ukey Compare arrays via a user-defined callback function (keys only) array_key_exists Checks if a specified key exists in an array, alternative: key_exists array_keys Returns all keys or a subset of keys in an array array_map Applies a callback to the elements of a given array array_merge Merge one or several arrays array_merge_recursive Merge one or more arrays recursively array_multisort Sorts multiple or multi-dimensional arrays array_pad Inserts a specified number of items (with a specified value) into an array array_pop Deletes an element from the end of an array array_product Calculate the product of all values in an array array_push Push one or several elements to the end of the array WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​9
array_rand Pick one or more random entries out of an array array_reduce Reduce the array to a single string using a user-defined function array_replace Replaces elements in the first array with values from following arrays array_replace_recursive Recursively replaces elements from later arrays into the first array array_reverse Returns an array in reverse order array_search Searches the array for a given value and returns the first key if successful array_shift Shifts an element from the beginning of an array array_slice Extracts a slice of an array array_splice Removes a portion of the array and replaces it array_sum Calculate the sum of the values in an array array_udiff Compare arrays and return the difference using a user function (values only) array_udiff_assoc Compare arrays and return the difference using a default and a user function (keys and values) array_udiff_uassoc Compare arrays and return the difference using two user functions (values and keys) array_uintersect WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​10
Compare arrays and return the matches via user function (values only) array_uintersect_assoc Compare arrays and return the matches via a default user function (keys and values) array_uintersect_uassoc Compare arrays and return the matches via two user functions (keys and values) array_unique Removes duplicate values from an array array_unshift Adds one or more elements to the beginning of an array array_values Returns all values of an array array_walk Applies a user function to every element in an array array_walk_recursive Recursively applies a user function to every element of an array arsort Sorts an associative array in descending order according to the value asort Sorts an associative array in ascending order according to the value compact Create an array containing variables and their values count Count all elements in an array, alternatively use sizeof current Returns the current element in an array, an alternative is pos each Return the current key and value pair from an array end WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​11
Set the internal pointer to the last element of an array extract Import variables from an array into the current symbol table in_array Checks if a value exists in an arraykeyFetches a key from an array krsort Sorts an associative array by key in reverse order ksort Sorts an associative array by key list Assigns variables as if they were an array natcasesort Sorts an array using a “natural order” algorithm independent of case natsort Sorts an array using a “natural order” algorithm next Advance the internal pointer of an array prev Move the internal array pointer backwards range Creates an array from a range of elements reset Set the internal array pointer to its first element rsort Sort an array in reverse order shuffle Shuffle an array sort WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​12
Sorts an indexed array in ascending order uasort Sorts an array with a user-defined comparison function uksort Arrange an array by keys using a user-defined comparison function usort Categorize an array by values using a comparison function defined by the user PHP STRINGS Defining Strings Single quotes This is the simplest way. Just wrap your text in ' markers and PHP will handle it as a string. Double quotes As an alternative you can use ". When you do, it’s possible to use the escape characters below to display special characters. heredoc Begin a string with <<< and an identifier, then put the string in a new line. Close it in another line by repeating the identifier. heredoc behaves like double-quoted strings. nowdoc Is what heredoc is for double-quoted strings but for single quotes. It works the same way and eliminates the need for escape characters. Escape Characters n — Line feed r — Carriage return t — Horizontal tab v — Vertical tab e — Escape f — Form feed — Backslash $ — Dollar sign WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​13
’ — Single quote " — Double quote [0-7]{1,3} — Character in octal notation x[0-9A-Fa-f]{1,2} — Character in hexadecimal notation u{[0-9A-Fa-f]+} — String as UTF-8 representation String Functions addcslashes() Returns a string with backslashes in front of specified characters addslashes() Returns a string with backslashes in front of characters that need to be escaped bin2hex() Converts a string of ASCII characters to hexadecimal values chop() Removes space or other characters from the right end of a string chr() Returns a character from a specified ASCII value chunk_split() Splits a string into a series of smaller chunks convert_cyr_string() Converts a string from a Cyrillic character set to anotherconvert_uudecode() Decodes a uuencoded stringconvert_uuencode() Encodes a string using uuencodecount_chars() Returns information about the characters in a string crc32() Calculates a 32-bit CRC for a string crypt() WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​14
Returns a hashed string echo() or echo '' Outputs one or several strings explode() Breaks down a string into an array fprintf() Writes a formatted string to a specified output stream get_html_translation_table() Returns the translation table used by htmlspecialchars() and htmlentities() hebrev() Transforms Hebrew text to visual texthebrevc() Converts Hebrew text to visual text and implements HTML line breaks hex2bin() Translate hexadecimal values to ASCII characters html_entity_decode() Turns HTML entities to characters htmlentities() Converts characters to HTML entities htmlspecialchars_decode() Transforms special HTML entities to characters htmlspecialchars() Switches predefined characters to HTML entities implode() Retrieves a string from the elements of an array, same as join() lcfirst() Changes a string’s first character to lowercase levenshtein() WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​15
Calculates the Levenshtein distance between two strings localeconv() Returns information about numeric and monetary formatting for the locale ltrim() Removes spaces or other characters from the left side of a string md5() Calculates the MD5 hash of a string and returns it md5_file() Calculates the MD5 hash of a file metaphone() Provides the metaphone key of a string money_format() Returns a string as a currency string nl_langinfo() Gives specific locale information nl2br() Inserts HTML line breaks for each new line in a string number_format() Formats a number including grouped thousands ord() Returns the ASCII value of a string’s first character parse_str() Parses a string into variables print() Outputs one or several strings printf() Outputs a formatted string quoted_printable_decode() WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​16
Converts a quoted-printable string to 8-bit binary quoted_printable_encode() Goes from 8-bit string to a quoted-printable string quotemeta() Returns a string with a backslash before metacharacters rtrim() Strips whitespace or other characters from the right side of a string setlocale() Sets locale information sha1() Calculates a string’s SHA-1 hash sha1_file() Does the same for a file similar_text() Determines the similarity between two strings soundex() Calculates the soundex key of a string sprintf() Returns a formatted string sscanf() Parses input from a string according to a specified format str_getcsv() Parses a CSV string into an array str_ireplace() Replaces specified characters in a string with specified replacements (case-insensitive) str_pad() Pads a string to a specified length str_repeat() WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​17
Repeats a string a preset number of times str_replace() Replaces specified characters in a string (case-sensitive) str_rot13() Performs ROT13 encoding on a string str_shuffle() Randomly shuffles the characters in a string str_split() Splits strings into arrays str_word_count() Returns the number of words in a string strcasecmp() Case-insensitive comparison of two strings strcmp() Binary safe string comparison (case sensitive) strcoll() Compares two strings based on locale strcspn() Returns the number of characters found in a string before the occurrence of specified characters strip_tags() Removes HTML and PHP tags from a string stripcslashes() Opposite of addcslashes() stripslashes() Opposite of addslashes() stripos() Finds the position of the first occurrence of a substring within a string (case insensitive) stristr() WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​18
Case-insensitive version of strstr() strlen() Returns the length of a string strnatcasecmp() Case-insensitive comparison of two strings using a “natural order” algorithm strnatcmp() Same as the aforementioned but case sensitive strncasecmp() String comparison of a defined number of characters (case insensitive) strncmp() Same as above but case-sensitive strpbrk() Searches a string for any number of characters strpos() Returns the position of the first occurrence of a substring in a string (case sensitive) strrchr() Finds the last occurrence of a string within another string strrev() Reverses a string strripos() Finds the position of the last occurrence of a string’s substring (case insensitive) strrpos() Same as strripos() but case sensitive strspn() The number of characters in a string with only characters from a specified list strstr() WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​19
Case-sensitive search for the first occurrence of a string inside another string strtok() Splits a string into smaller chunks strtolower() Converts all characters in a string to lowercase strtoupper() Same but for uppercase letters strtr() Translates certain characters in a string, alternative: strchr() substr() Returns a specified part of a string substr_compare() Compares two strings from a specified start position up to a certain length, optionally case sensitive substr_count() Counts the number of times a substring occurs within a string substr_replace() Replaces a substring with something else trim() Removes space or other characters from both sides of a string ucfirst() Transforms the first character of a string to uppercase ucwords() Converts the first character of every word in a string to uppercase vfprintf() Writes a formatted string to a specified output stream vprintf() Outputs a formatted string vsprintf() WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​20
Writes a formatted string to a variable wordwrap() Shortens a string to a given number of characters PHP OPERATORS Arithmetic Operators + — Addition - — Subtraction * — Multiplication / — Division % — Modulo (the remainder of value divided by another) ** — Exponentiation Assignment Operators += — a += b is the same as a = a + b -= — a -= b is the same as a = a – b *= — a *= b is the same as a = a * b /= — a /= b is the same as a = a / b %= — a %= b is the same as a = a % b Comparison Operators == — Equal === — Identical != — Not equal <> — Not equal !== — Not identical < — Less than > — Greater than <= — Less than or equal to >= — Greater than or equal to <=> — Less than, equal to, or greater than Logical Operators and — And or — Or xor — Exclusive or ! — Not && — And || — Or WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​21
Bitwise Operators & — And | — Or (inclusive or) ^ — Xor (exclusive or) ~ — Not << — Shift left >> — Shift right Error Control Operator You can use the @ sign to prevent expressions from generating error messages. This is often important for security reasons, for example to keep confidential information safe. Execution Operator PHP supports one execution operator, which is `` (backticks). These are not single-quotes! PHP will attempt to execute the contents of the backticks as a shell command. Increment/Decrement Operators ++$v Increments a variable by one, then returns it $v++ Returns a variable, then increments it by one --$v Decrements the variable by one, returns it afterward $v-- Returns the variable then decrements it by one String Operators . Used to concatenate (mean combine) arguments .= Used to append the argument on the right to the left-side argument WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​22
LOOPS IN PHP For Loop for (starting counter value; ending counter value; increment by which to increase) { // code to execute goes here } Foreach Loop foreach ($InsertYourArrayName as $value) { // code to execute goes here } While Loop while (condition that must apply) { // code to execute goes here } Do..While Loop do { // code to execute goes here; } while (condition that must apply); CONDITIONAL STATEMENTS If Statement if (condition) { // code to execute if condition is met } If..Else if (condition) { // code to execute if condition is met } else { // code to execute if condition is not met } WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​23
If..Elseif..Else if (condition) { // code to execute if condition is met } elseif (condition) { // code to execute if this condition is met } else { // code to execute if none of the conditions are met } Switch Statement switch (n) { case x: code to execute if n=x; break; case y: code to execute if n=y; break; case z: code to execute if n=z; break; // add more cases as needed default: code to execute if n is neither of the above; } WORKING WITH FORMS IN PHP Using GET vs POST GET collects data via URL parameters. That means all variable names and their values are contained in the page address. The advantage of this is that you’re able to bookmark the information. Keep in mind that it also means that the information is visible to everyone. For that reason, GET is not suitable for sensitive information such as passwords. It also limits the amount of data that can be sent in ca 2000 characters. POST, on the other hand, uses the HTTP POST method to pass on variables. This makes the data invisible to third parties, as it is sent in the HTTP body. You are not able to bookmark it. WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​24
With POST, there are no limits to the amount of information you can send. Aside from that, it also has advanced functionality and is therefore preferred by developers. Form Security PHP offers tools to thwart those attacks, namely: htmlspecialchars() trim() stripslashes() Required Fields, Error Messages and Data Validation Aside from that, PHP is able to define required fields (you can’t submit the form without filling them out), display error messages if some information is missing and to validate data. We have already talked about the necessary tools to do so. For example, you can simply define variables for your form fields and use the empty() function to check if they have values. After that, create a simple if/else statement to either send the submitted data or output an error message. The next step is to check submitted data for validity. For that, PHP offers a number of filters such as FILTER_VALIDATE_EMAIL to make sure a submitted email address has the right format. Regular Expressions (RegEx) Syntax $exp = "/w3schools/i"; RegEx Functions preg_match() Returns 1 if the pattern was found in the string and 0 if not preg_match_all() Returns the number of times the pattern was found in the string, which may also be 0 WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​25
preg_replace() Returns a new string where matched patterns have been replaced with another string RegEx Modifiers i Performs a case-insensitive search m Performs a multiline search (patterns that search for the beginning or end of a string will match the beginning or end of each line) u Enables correct matching of UTF-8 encoded patterns RegEx Patterns [abc] - Find one character from the options between the brackets [^abc] - Find any character NOT between the brackets [0-9] - Find one character from the range 0 to 9 Metacharacters | Find a match for any one of the patterns separated by | as in: cat|dog|fish . Find just one instance of any character ^ Finds a match as the beginning of a string as in: ^Hello $ Finds a match at the end of the string as in: World$ d Find a digit s Find a whitespace character WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​26
b Find a match at the beginning of a word like this: bWORD, or at the end of a word like this: WORDb uxxxx Find the Unicode character specified by the hexadecimal number xxxx Quantifiers n+ Matches any string that contains at least one n n* Matches any string that contains zero or more occurrences of n n? Matches any string that contains zero or one occurrences of n n{x} Matches any string that contains a sequence of X n's n{x,y} Matches any string that contains a sequence of X to Y n's n{x,} Matches any string that contains a sequence of at least X n's Grouping Use parentheses ( ) to apply quantifiers to entire patterns. They cal also be used to select parts of the pattern to be used as a match. <?php $str = "Apples and bananas."; $pattern = "/ba(na){2}/i"; echo preg_match($pattern, $str); // Outputs 1 ?> WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​27
PHP Functions ● A function is a block of statements that can be used repeatedly in a program. ● A function will not execute automatically when a page loads. ● A function will be executed by a call to the function. Syntax function functionName() { code to be executed; } functionName(); Function Arguments <?php function familyName($fname, $year) { echo "$fname Refsnes. Born in $year <br>"; } familyName("Hege", "1975"); familyName("Stale", "1978"); familyName("Kai Jim", "1983"); ?> Default Argument Value <?php declare(strict_types=1); // strict requirement function setHeight(int $minheight = 50) { echo "The height is : $minheight <br>"; } setHeight(350); setHeight(); // will use the default value of 50 setHeight(135); setHeight(80); ?> Returning values <?php declare(strict_types=1); // strict requirement function sum(int $x, int $y) { $z = $x + $y; return $z; } echo "5 + 10 = " . sum(5, 10) . "<br>"; echo "7 + 13 = " . sum(7, 13) . "<br>"; echo "2 + 4 = " . sum(2, 4); ?> WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​28
PHP FILTERS Filter Functions filter_has_var() Checks if a variable of the specified type exists filter_id() Returns the ID belonging to a named filter filter_input() Retrieves a specified external variable by name and optionally filters it filter_input_array() Pulls external variables and optionally filters them filter_list() Returns a list of all supported filters filter_var_array() Gets multiple variables and optionally filters them filter_var() Filters a variable with a specified filter Filter Constants FILTER_VALIDATE_BOOLEAN Validates a boolean FILTER_VALIDATE_EMAIL Certifies an e-mail address FILTER_VALIDATE_FLOAT Confirms a float FILTER_VALIDATE_INT Verifies an integer WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​29
FILTER_VALIDATE_IP Validates an IP address FILTER_VALIDATE_REGEXP Confirms a regular expression FILTER_VALIDATE_URL Validates a URL FILTER_SANITIZE_EMAIL Removes all illegal characters from an e-mail address FILTER_SANITIZE_ENCODED Removes/Encodes special characters FILTER_SANITIZE_MAGIC_QUOTES Applies addslashes() FILTER_SANITIZE_NUMBER_FLOAT Removes all characters, except digits, +- and .,eE FILTER_SANITIZE_NUMBER_INT Gets rid of all characters except digits and + – FILTER_SANITIZE_SPECIAL_CHARS Removes special characters FILTER_SANITIZE_FULL_SPECIAL_CHARS Converts special characters to HTML entities FILTER_SANITIZE_STRING Removes tags/special characters from a string, alternative: FILTER_SANITIZE_STRIPPED FILTER_SANITIZE_URL Rids all illegal characters from a URL FILTER_UNSAFE_RAW Do nothing, optionally strip/encode special characters FILTER_CALLBACK Call a user-defined function to filter data WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​30
HTTP FUNCTIONS IN PHP HTTP Functions header() Sends a raw HTTP header to the browser headers_list() A list of response headers ready to send (or already sent) headers_sent() Checks if and where the HTTP headers have been sent setcookie() Defines a cookie to be sent along with the rest of the HTTP headers setrawcookie() Defines a cookie (without URL encoding) to be sent along WORKING WITH MYSQL MySQL Functions mysqli_affected_rows() The number of affected rows in the previous MySQL operation mysqli_autocommit() Turn auto-committing database modifications on or off mysqli_change_user() Changes the user of the specified database connection mysqli_character_set_name() The default character set for the database connection mysqli_close() Closes an open database connection mysqli_commit() Commits the current transaction WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​31
mysqli_connect_errno() The error code from the last connection error mysqli_connect_error() The error description from the last connection error mysqli_connect() Opens a new connection to the MySQL server mysqli_data_seek() Moves the result pointer to an arbitrary row in the result set mysqli_debug() Performs debugging operations mysqli_dump_debug_info() Dumps debugging information into a log mysqli_errno() The last error code for the most recent function call mysqli_error_list() A list of errors for the most recent function call mysqli_error() The last error description for the most recent function call mysqli_fetch_all() Fetches all result rows as an array mysqli_fetch_array() Fetches a result row as an associative, a numeric array, or both mysqli_fetch_assoc() Fetches a result row as an associative array mysqli_fetch_field_direct() Metadata for a single field as an object mysqli_fetch_field() The next field in the result set as an object WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​32
mysqli_fetch_fields() An array of objects that represent the fields in a result set mysqli_fetch_lengths() The lengths of the columns of the current row in the result set mysqli_fetch_object() The current row of a result set as an object mysqli_fetch_row() Fetches one row from a result set and returns it as an enumerated array mysqli_field_count() The number of columns for the most recent query mysqli_field_seek() Sets the field cursor to the given field offset mysqli_field_tell() The position of the field cursor mysqli_free_result() Frees the memory associated with a result mysqli_get_charset() A character set object mysqli_get_client_info() The MySQL client library version mysqli_get_client_stats() Returns client per-process statistics mysqli_get_client_version() The MySQL client library version as an integer mysqli_get_connection_stats() Statistics about the client connection mysqli_get_host_info() The MySQL server hostname and the connection type WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​33
mysqli_get_proto_info() The MySQL protocol version mysqli_get_server_info() Returns the MySQL server version mysqli_get_server_version() The MySQL server version as an integer mysqli_info() Returns information about the most recently executed query mysqli_init() Initializes MySQLi and returns a resource for use with mysqli_real_connect() mysqli_insert_id() Returns the auto-generated ID used in the last query mysqli_kill() Asks the server to kill a MySQL thread mysqli_more_results() Checks if there are more results from a multi query mysqli_multi_query() Performs one or more queries on the database mysqli_next_result() Prepares the next result set from mysqli_multi_query() mysqli_num_fields() The number of fields in a result set mysqli_num_rows() The number of rows in a result set mysqli_options() Sets extra connect options and affect behavior for a connection mysqli_ping() Pings a server connection or tries to reconnect if it has gone down WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​34
mysqli_prepare() Prepares an SQL statement for execution mysqli_query() Performs a query against the database mysqli_real_connect() Opens a new connection to the MySQL server mysqli_real_escape_string() Escapes special characters in a string for use in an SQL statement mysqli_real_query() Executes an SQL query mysqli_reap_async_query() Returns the result from async query mysqli_refresh() Refreshes tables or caches or resets the replication server information mysqli_rollback() Rolls back the current transaction for the database mysqli_select_db() Changes the default database for the connection mysqli_set_charset() Sets the default client character set mysqli_set_local_infile_default() Unsets a user-defined handler for the LOAD LOCAL INFILE command mysqli_set_local_infile_handler() Sets a callback function for the LOAD DATA LOCAL INFILE command mysqli_sqlstate() Returns the SQLSTATE error code for the last MySQL operation mysqli_ssl_set() Establishes secure connections using SSL WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​35
mysqli_stat() The current system status mysqli_stmt_init() Initializes a statement and returns an object for use with mysqli_stmt_prepare() mysqli_store_result() Transfers a result set from the last query mysqli_thread_id() The thread ID for the current connection mysqli_thread_safe() Returns if the client library is compiled as thread-safe mysqli_use_result() Initiates the retrieval of a result set from the last query executed using the mysqli_real_query() mysqli_warning_count() The number of warnings from the last query in the connection DATE AND TIME Date/Time Functions checkdate() Checks the validity of a Gregorian date date_add() Adds a number of days, months, years, hours, minutes and seconds to a date object date_create_from_format() Returns a formatted DateTime object date_create() Creates a new DateTime object date_date_set() Sets a new date WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​36
date_default_timezone_get() Returns the default timezone used by all functions date_default_timezone_set() Sets the default timezone date_diff() Calculates the difference between two dates date_format() Returns a date formatted according to a specific format date_get_last_errors() Returns warnings or errors found in a date string date_interval_create_from_date_string() Sets up a DateInterval from relative parts of a string date_interval_format() Formats an interval date_isodate_set() Sets a date according to ISO 8601 standards date_modify() Modifies the timestamp date_offset_get() Returns the offset of the timezone date_parse_from_format() Returns an array with detailed information about a specified date, according to a specified format date_parse() Returns an array with detailed information about a specified date date_sub() Subtracts days, months, years, hours, minutes and seconds from a date date_sun_info() Returns an array containing information about sunset/sunrise and twilight begin/end for a specified day and location WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​37
date_sunrise() The sunrise time for a specified day and location date_sunset() The sunset time for a specified day and location date_time_set() Sets the time date_timestamp_get() Returns the Unix timestamp date_timestamp_set() Sets the date and time based on a Unix timestamp date_timezone_get() Returns the time zone of a given DateTime object date_timezone_set() Sets the time zone for a DateTime object date() Formats a local date and time getdate() Date/time information of a timestamp or the current local date/time gettimeofday() The current time gmdate() Formats a GMT/UTC date and time gmmktime() The Unix timestamp for a GMT date gmstrftime() Formats a GMT/UTC date and time according to locale settings idate() Formats a local time/date as an integer WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​38
localtime() The local time microtime() The current Unix timestamp with microseconds mktime() The Unix timestamp for a date strftime() Formats a local time and/or date according to locale settings strptime() Parses a time/date generated with strftime() strtotime() Transforms an English textual DateTime into a Unix timestamp time() The current time as a Unix timestamp timezone_abbreviations_list() Returns an array containing dst, offset, and the timezone name timezone_identifiers_list() An indexed array with all timezone identifiers timezone_location_get() Location information for a specified timezone timezone_name_from_abbr() Returns the timezone name from an abbreviation timezone_name_get() The name of the timezone timezone_offset_get() The timezone offset from GMT timezone_open() Creates a new DateTimeZone object WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​39
timezone_transitions_get() Returns all transitions for the timezone timezone_version_get() Returns the version of the timezonedb Date and Time Formatting d — 01 to 31 j — 1 to 31 D — Mon through Sun l — Sunday through Saturday N — 1 (for Mon) through 7 (for Sat) w — 0 (for Sun) through 6 (for Sat) m — Months, 01 through 12 n — Months, 1 through 12 F — January through December M — Jan through Dec Y — Four digits year (e.g. 2018) y — Two digits year (e.g. 18) L — Defines whether it’s a leap year (1 or 0) a — am and pm A — AM and PM g — Hours 1 through 12 h — Hours 01 through 12 G — Hours 0 through 23 H — Hours 00 through 23 i — Minutes 00 to 59 s — Seconds 00 to 59 PHP ERRORS Error Functions debug_backtrace() Used to generate a backtrace debug_print_backtrace() Prints a backtrace error_get_last() Gets the last error that occurred WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​40
error_log() Sends an error message to the web server’s log, a file or a mail account error_reporting() Specifies which PHP errors are reported restore_error_handler() Reverts to the previous error handler function restore_exception_handler() Goes back to the previous exception handler set_error_handler() Sets a user-defined function to handle script errors set_exception_handler() Sets an exception handler function defined by the user trigger_error() Generates a user-level error message, you can also use user_error() Error Constants E_ERROR Fatal run-time errors that cause the halting of the script and can’t be recovered from E_WARNING Non-fatal run-time errors, execution of the script continues E_PARSE Compile-time parse errors, should only be generated by the parser E_NOTICE Run-time notices that indicate a possible error E_CORE_ERROR Fatal errors at PHP initialization, like an E_ERROR in PHP core E_CORE_WARNING Non-fatal errors at PHP startup, similar to E_WARNING but in PHP core WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​41
E_COMPILE_ERROR Fatal compile-time errors generated by the Zend Scripting Engine E_COMPILE_WARNING Non-fatal compile-time errors by the Zend Scripting Engine E_USER_ERROR Fatal user-generated error, set by the programmer using trigger_error() E_USER_WARNING Non-fatal user-generated warning E_USER_NOTICE User-generated notice by trigger_error() E_STRICT Suggestions by PHP to improve your code (needs to be enabled) E_RECOVERABLE_ERROR Catchable fatal error caught by a user-defined handle E_DEPRECATED Enable this to receive warnings about a code which is not future-proof E_USER_DEPRECATED User-generated warning for deprecated code E_ALL All errors and warnings except E_STRICT WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​42

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PHP-Cheat-Sheet.pdf

  • 1. Beginner’s Essential PHP CHEAT SHEET Fast, flexible and pragmatic scripting language.
  • 2. Table of Contents PHP Basics 2 Variables and Constants 2 PHP Arrays - Grouped Values 7 PHP Strings 13 PHP Operators 21 Loops in PHP 23 Conditional Statements 23 Working with Forms in PHP 24 Regular Expressions 26 PHP Functions 28 PHP Filters 29 HTTP Functions in PHP 31 Working with MySQL 31 Date and Time 36 PHP Errors 40 WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​1
  • 3. PHP BASICS Including PHP in a File <?php // place PHP code here ?> Writing Comments // Denotes comments that only span on one line # Another way of producing single-line comments /*...*/ Everything between /* and */ is not executed, also works across several lines Outputting Data <?php echo "<h1>PHP Cheat Sheet</h1>"; ?> Writing PHP Functions function NameOfTheFunction() { //place PHP code here } VARIABLES AND CONSTANTS Defining Variables <?php $BlogPostTitle = "PHP Cheat Sheet"; ?> WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​2
  • 4. Types of Data Integers Integers are non-decimal numbers between -2,147,483,648 and 2,147,483,647. They must have at least one digit and no decimal point. Can be in decimal, hexadecimal or octal. Floats This is the name for numbers with a decimal point or in exponential form. Strings This simply means text, we will talk about it in detail further below. Boolean values Meaning true/false statements. Arrays Arrays are variables that store several values. We will talk about them in detail further below. Objects Objects store both data and information on how to process it. Resources These are references to functions and resources outside of PHP. NULL A variable that is NULL doesn’t have any value. Variable Scope function myFunction() { global $a, $b; $b = $a - $b; } WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​3
  • 5. Predefined Variables $GLOBALS Used to access global variables from anywhere inside a PHP script​. $_SERVER Contains information about the locations of headers, paths and scripts. $_GET Can collect data that was sent in the URL or submitted in an HTML form. $_POST Used to gather data from an HTML form and to pass variables. $_REQUEST Also collects data after submitting an HTML form Variable-handling Functions boolval Used to retrieve the boolean value of a variable debug_zval_dump Outputs a string representation of an internal zend value empty Checks whether a variable is empty or not floatval Get the float value of a variable (doubleval is another possibility) get_defined_vars Returns an array of all defined variables get_resource_type Returns the resource type gettype Retrieves the variable type WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​4
  • 6. import_request_variables Import GET/POST/Cookie variables into the global scope intval Find the integer value of a variable is_array Checks whether a variable is an array is_bool Finds out if a variable is a boolean​ of 538 is_callable Verify whether you can call the contents of a variable as a function is_countable Check whether the contents of a variable are countable is_float Find out if the type of a variable is float, alternatives: is_double and is_real is_int Check if the type of a variable is an integer, is_integer and is_long also works is_iterable Verify that a variable’s content is an iterable value is_null Checks whether a variable’s value is NULL is_numeric Find out if a variable is a number or a numeric string is_object Determines whether a variable is an object is_resource Check if a variable is a resource is_scalar Tests if a variable is a scalar WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​5
  • 7. is_string Find out whether the type of a variable is a string isset Determine if a variable has been set and is not NULL print_r Provides human-readable information about a variable serialize Generates a representation of a value that is storable settype Sets a variable’s type strval Retrieves the string value of a variable unserialize Creates a PHP value from a stored representation unset Unsets a variable var_dump Dumps information about a variable var_export Outputs or returns a string representation of a variable that can be parsed Constants define(name, value, true/false) Aside from user-defined constants, there also a number of default PHP constants: __LINE__ Denotes the number of the current line in a file __FILE__ Is the full path and filename of the file WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​6
  • 8. __DIR__ The directory of the file __FUNCTION__ Name of the function __CLASS__ Class name, includes the namespace it was declared in __TRAIT__ The trait name, also includes the namespace __METHOD__ The class method name __NAMESPACE__ Name of the current namespace PHP ARRAYS – GROUPED VALUES Indexed arrays Arrays that have a numeric index Associative arrays Arrays where the keys are named Multidimensional arrays Arrays that contain one or more other arrays Declaring an Array in PHP <?php $cms = array("WordPress", "Joomla", "Drupal"); echo "What is your favorite CMS? Is it " . $cms[0] . ", " . $cms[1] . " or " . $cms[2] . "?"; ?> Array Functions array_change_key_case Changes all keys in an array to uppercase or lowercase WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​7
  • 9. array_chunk Splits an array into chunks array_column Retrieves the values from a single column in an array array_combine Merges the keys from one array and the values from another into a new array array_count_values Counts all values in an array array_diff Compares arrays, returns the difference (values only array_diff_assoc Compares arrays, returns the difference (values and keys) array_diff_key Compares arrays, returns the difference (keys only) array_diff_uassoc Compares arrays (keys and values) through a user callback function array_diff_ukey Compares arrays (keys only) through a user callback function array_fill Fills an array with values array_fill_keys Fills an array with values, specifying keys array_filter Filters the elements of an array via a callback function array_flip Exchanges all keys in an array with their associated values array_intersect Compare arrays and return their matches (values only) WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​8
  • 10. array_intersect_assoc Compare arrays and return their matches (keys and values) array_intersect_key Compare arrays and return their matches (keys only) array_intersect_uassoc Compare arrays via a user-defined callback function (keys and values) array_intersect_ukey Compare arrays via a user-defined callback function (keys only) array_key_exists Checks if a specified key exists in an array, alternative: key_exists array_keys Returns all keys or a subset of keys in an array array_map Applies a callback to the elements of a given array array_merge Merge one or several arrays array_merge_recursive Merge one or more arrays recursively array_multisort Sorts multiple or multi-dimensional arrays array_pad Inserts a specified number of items (with a specified value) into an array array_pop Deletes an element from the end of an array array_product Calculate the product of all values in an array array_push Push one or several elements to the end of the array WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​9
  • 11. array_rand Pick one or more random entries out of an array array_reduce Reduce the array to a single string using a user-defined function array_replace Replaces elements in the first array with values from following arrays array_replace_recursive Recursively replaces elements from later arrays into the first array array_reverse Returns an array in reverse order array_search Searches the array for a given value and returns the first key if successful array_shift Shifts an element from the beginning of an array array_slice Extracts a slice of an array array_splice Removes a portion of the array and replaces it array_sum Calculate the sum of the values in an array array_udiff Compare arrays and return the difference using a user function (values only) array_udiff_assoc Compare arrays and return the difference using a default and a user function (keys and values) array_udiff_uassoc Compare arrays and return the difference using two user functions (values and keys) array_uintersect WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​10
  • 12. Compare arrays and return the matches via user function (values only) array_uintersect_assoc Compare arrays and return the matches via a default user function (keys and values) array_uintersect_uassoc Compare arrays and return the matches via two user functions (keys and values) array_unique Removes duplicate values from an array array_unshift Adds one or more elements to the beginning of an array array_values Returns all values of an array array_walk Applies a user function to every element in an array array_walk_recursive Recursively applies a user function to every element of an array arsort Sorts an associative array in descending order according to the value asort Sorts an associative array in ascending order according to the value compact Create an array containing variables and their values count Count all elements in an array, alternatively use sizeof current Returns the current element in an array, an alternative is pos each Return the current key and value pair from an array end WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​11
  • 13. Set the internal pointer to the last element of an array extract Import variables from an array into the current symbol table in_array Checks if a value exists in an arraykeyFetches a key from an array krsort Sorts an associative array by key in reverse order ksort Sorts an associative array by key list Assigns variables as if they were an array natcasesort Sorts an array using a “natural order” algorithm independent of case natsort Sorts an array using a “natural order” algorithm next Advance the internal pointer of an array prev Move the internal array pointer backwards range Creates an array from a range of elements reset Set the internal array pointer to its first element rsort Sort an array in reverse order shuffle Shuffle an array sort WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​12
  • 14. Sorts an indexed array in ascending order uasort Sorts an array with a user-defined comparison function uksort Arrange an array by keys using a user-defined comparison function usort Categorize an array by values using a comparison function defined by the user PHP STRINGS Defining Strings Single quotes This is the simplest way. Just wrap your text in ' markers and PHP will handle it as a string. Double quotes As an alternative you can use ". When you do, it’s possible to use the escape characters below to display special characters. heredoc Begin a string with <<< and an identifier, then put the string in a new line. Close it in another line by repeating the identifier. heredoc behaves like double-quoted strings. nowdoc Is what heredoc is for double-quoted strings but for single quotes. It works the same way and eliminates the need for escape characters. Escape Characters n — Line feed r — Carriage return t — Horizontal tab v — Vertical tab e — Escape f — Form feed — Backslash $ — Dollar sign WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​13
  • 15. ’ — Single quote " — Double quote [0-7]{1,3} — Character in octal notation x[0-9A-Fa-f]{1,2} — Character in hexadecimal notation u{[0-9A-Fa-f]+} — String as UTF-8 representation String Functions addcslashes() Returns a string with backslashes in front of specified characters addslashes() Returns a string with backslashes in front of characters that need to be escaped bin2hex() Converts a string of ASCII characters to hexadecimal values chop() Removes space or other characters from the right end of a string chr() Returns a character from a specified ASCII value chunk_split() Splits a string into a series of smaller chunks convert_cyr_string() Converts a string from a Cyrillic character set to anotherconvert_uudecode() Decodes a uuencoded stringconvert_uuencode() Encodes a string using uuencodecount_chars() Returns information about the characters in a string crc32() Calculates a 32-bit CRC for a string crypt() WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​14
  • 16. Returns a hashed string echo() or echo '' Outputs one or several strings explode() Breaks down a string into an array fprintf() Writes a formatted string to a specified output stream get_html_translation_table() Returns the translation table used by htmlspecialchars() and htmlentities() hebrev() Transforms Hebrew text to visual texthebrevc() Converts Hebrew text to visual text and implements HTML line breaks hex2bin() Translate hexadecimal values to ASCII characters html_entity_decode() Turns HTML entities to characters htmlentities() Converts characters to HTML entities htmlspecialchars_decode() Transforms special HTML entities to characters htmlspecialchars() Switches predefined characters to HTML entities implode() Retrieves a string from the elements of an array, same as join() lcfirst() Changes a string’s first character to lowercase levenshtein() WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​15
  • 17. Calculates the Levenshtein distance between two strings localeconv() Returns information about numeric and monetary formatting for the locale ltrim() Removes spaces or other characters from the left side of a string md5() Calculates the MD5 hash of a string and returns it md5_file() Calculates the MD5 hash of a file metaphone() Provides the metaphone key of a string money_format() Returns a string as a currency string nl_langinfo() Gives specific locale information nl2br() Inserts HTML line breaks for each new line in a string number_format() Formats a number including grouped thousands ord() Returns the ASCII value of a string’s first character parse_str() Parses a string into variables print() Outputs one or several strings printf() Outputs a formatted string quoted_printable_decode() WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​16
  • 18. Converts a quoted-printable string to 8-bit binary quoted_printable_encode() Goes from 8-bit string to a quoted-printable string quotemeta() Returns a string with a backslash before metacharacters rtrim() Strips whitespace or other characters from the right side of a string setlocale() Sets locale information sha1() Calculates a string’s SHA-1 hash sha1_file() Does the same for a file similar_text() Determines the similarity between two strings soundex() Calculates the soundex key of a string sprintf() Returns a formatted string sscanf() Parses input from a string according to a specified format str_getcsv() Parses a CSV string into an array str_ireplace() Replaces specified characters in a string with specified replacements (case-insensitive) str_pad() Pads a string to a specified length str_repeat() WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​17
  • 19. Repeats a string a preset number of times str_replace() Replaces specified characters in a string (case-sensitive) str_rot13() Performs ROT13 encoding on a string str_shuffle() Randomly shuffles the characters in a string str_split() Splits strings into arrays str_word_count() Returns the number of words in a string strcasecmp() Case-insensitive comparison of two strings strcmp() Binary safe string comparison (case sensitive) strcoll() Compares two strings based on locale strcspn() Returns the number of characters found in a string before the occurrence of specified characters strip_tags() Removes HTML and PHP tags from a string stripcslashes() Opposite of addcslashes() stripslashes() Opposite of addslashes() stripos() Finds the position of the first occurrence of a substring within a string (case insensitive) stristr() WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​18
  • 20. Case-insensitive version of strstr() strlen() Returns the length of a string strnatcasecmp() Case-insensitive comparison of two strings using a “natural order” algorithm strnatcmp() Same as the aforementioned but case sensitive strncasecmp() String comparison of a defined number of characters (case insensitive) strncmp() Same as above but case-sensitive strpbrk() Searches a string for any number of characters strpos() Returns the position of the first occurrence of a substring in a string (case sensitive) strrchr() Finds the last occurrence of a string within another string strrev() Reverses a string strripos() Finds the position of the last occurrence of a string’s substring (case insensitive) strrpos() Same as strripos() but case sensitive strspn() The number of characters in a string with only characters from a specified list strstr() WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​19
  • 21. Case-sensitive search for the first occurrence of a string inside another string strtok() Splits a string into smaller chunks strtolower() Converts all characters in a string to lowercase strtoupper() Same but for uppercase letters strtr() Translates certain characters in a string, alternative: strchr() substr() Returns a specified part of a string substr_compare() Compares two strings from a specified start position up to a certain length, optionally case sensitive substr_count() Counts the number of times a substring occurs within a string substr_replace() Replaces a substring with something else trim() Removes space or other characters from both sides of a string ucfirst() Transforms the first character of a string to uppercase ucwords() Converts the first character of every word in a string to uppercase vfprintf() Writes a formatted string to a specified output stream vprintf() Outputs a formatted string vsprintf() WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​20
  • 22. Writes a formatted string to a variable wordwrap() Shortens a string to a given number of characters PHP OPERATORS Arithmetic Operators + — Addition - — Subtraction * — Multiplication / — Division % — Modulo (the remainder of value divided by another) ** — Exponentiation Assignment Operators += — a += b is the same as a = a + b -= — a -= b is the same as a = a – b *= — a *= b is the same as a = a * b /= — a /= b is the same as a = a / b %= — a %= b is the same as a = a % b Comparison Operators == — Equal === — Identical != — Not equal <> — Not equal !== — Not identical < — Less than > — Greater than <= — Less than or equal to >= — Greater than or equal to <=> — Less than, equal to, or greater than Logical Operators and — And or — Or xor — Exclusive or ! — Not && — And || — Or WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​21
  • 23. Bitwise Operators & — And | — Or (inclusive or) ^ — Xor (exclusive or) ~ — Not << — Shift left >> — Shift right Error Control Operator You can use the @ sign to prevent expressions from generating error messages. This is often important for security reasons, for example to keep confidential information safe. Execution Operator PHP supports one execution operator, which is `` (backticks). These are not single-quotes! PHP will attempt to execute the contents of the backticks as a shell command. Increment/Decrement Operators ++$v Increments a variable by one, then returns it $v++ Returns a variable, then increments it by one --$v Decrements the variable by one, returns it afterward $v-- Returns the variable then decrements it by one String Operators . Used to concatenate (mean combine) arguments .= Used to append the argument on the right to the left-side argument WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​22
  • 24. LOOPS IN PHP For Loop for (starting counter value; ending counter value; increment by which to increase) { // code to execute goes here } Foreach Loop foreach ($InsertYourArrayName as $value) { // code to execute goes here } While Loop while (condition that must apply) { // code to execute goes here } Do..While Loop do { // code to execute goes here; } while (condition that must apply); CONDITIONAL STATEMENTS If Statement if (condition) { // code to execute if condition is met } If..Else if (condition) { // code to execute if condition is met } else { // code to execute if condition is not met } WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​23
  • 25. If..Elseif..Else if (condition) { // code to execute if condition is met } elseif (condition) { // code to execute if this condition is met } else { // code to execute if none of the conditions are met } Switch Statement switch (n) { case x: code to execute if n=x; break; case y: code to execute if n=y; break; case z: code to execute if n=z; break; // add more cases as needed default: code to execute if n is neither of the above; } WORKING WITH FORMS IN PHP Using GET vs POST GET collects data via URL parameters. That means all variable names and their values are contained in the page address. The advantage of this is that you’re able to bookmark the information. Keep in mind that it also means that the information is visible to everyone. For that reason, GET is not suitable for sensitive information such as passwords. It also limits the amount of data that can be sent in ca 2000 characters. POST, on the other hand, uses the HTTP POST method to pass on variables. This makes the data invisible to third parties, as it is sent in the HTTP body. You are not able to bookmark it. WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​24
  • 26. With POST, there are no limits to the amount of information you can send. Aside from that, it also has advanced functionality and is therefore preferred by developers. Form Security PHP offers tools to thwart those attacks, namely: htmlspecialchars() trim() stripslashes() Required Fields, Error Messages and Data Validation Aside from that, PHP is able to define required fields (you can’t submit the form without filling them out), display error messages if some information is missing and to validate data. We have already talked about the necessary tools to do so. For example, you can simply define variables for your form fields and use the empty() function to check if they have values. After that, create a simple if/else statement to either send the submitted data or output an error message. The next step is to check submitted data for validity. For that, PHP offers a number of filters such as FILTER_VALIDATE_EMAIL to make sure a submitted email address has the right format. Regular Expressions (RegEx) Syntax $exp = "/w3schools/i"; RegEx Functions preg_match() Returns 1 if the pattern was found in the string and 0 if not preg_match_all() Returns the number of times the pattern was found in the string, which may also be 0 WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​25
  • 27. preg_replace() Returns a new string where matched patterns have been replaced with another string RegEx Modifiers i Performs a case-insensitive search m Performs a multiline search (patterns that search for the beginning or end of a string will match the beginning or end of each line) u Enables correct matching of UTF-8 encoded patterns RegEx Patterns [abc] - Find one character from the options between the brackets [^abc] - Find any character NOT between the brackets [0-9] - Find one character from the range 0 to 9 Metacharacters | Find a match for any one of the patterns separated by | as in: cat|dog|fish . Find just one instance of any character ^ Finds a match as the beginning of a string as in: ^Hello $ Finds a match at the end of the string as in: World$ d Find a digit s Find a whitespace character WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​26
  • 28. b Find a match at the beginning of a word like this: bWORD, or at the end of a word like this: WORDb uxxxx Find the Unicode character specified by the hexadecimal number xxxx Quantifiers n+ Matches any string that contains at least one n n* Matches any string that contains zero or more occurrences of n n? Matches any string that contains zero or one occurrences of n n{x} Matches any string that contains a sequence of X n's n{x,y} Matches any string that contains a sequence of X to Y n's n{x,} Matches any string that contains a sequence of at least X n's Grouping Use parentheses ( ) to apply quantifiers to entire patterns. They cal also be used to select parts of the pattern to be used as a match. <?php $str = "Apples and bananas."; $pattern = "/ba(na){2}/i"; echo preg_match($pattern, $str); // Outputs 1 ?> WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​27
  • 29. PHP Functions ● A function is a block of statements that can be used repeatedly in a program. ● A function will not execute automatically when a page loads. ● A function will be executed by a call to the function. Syntax function functionName() { code to be executed; } functionName(); Function Arguments <?php function familyName($fname, $year) { echo "$fname Refsnes. Born in $year <br>"; } familyName("Hege", "1975"); familyName("Stale", "1978"); familyName("Kai Jim", "1983"); ?> Default Argument Value <?php declare(strict_types=1); // strict requirement function setHeight(int $minheight = 50) { echo "The height is : $minheight <br>"; } setHeight(350); setHeight(); // will use the default value of 50 setHeight(135); setHeight(80); ?> Returning values <?php declare(strict_types=1); // strict requirement function sum(int $x, int $y) { $z = $x + $y; return $z; } echo "5 + 10 = " . sum(5, 10) . "<br>"; echo "7 + 13 = " . sum(7, 13) . "<br>"; echo "2 + 4 = " . sum(2, 4); ?> WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​28
  • 30. PHP FILTERS Filter Functions filter_has_var() Checks if a variable of the specified type exists filter_id() Returns the ID belonging to a named filter filter_input() Retrieves a specified external variable by name and optionally filters it filter_input_array() Pulls external variables and optionally filters them filter_list() Returns a list of all supported filters filter_var_array() Gets multiple variables and optionally filters them filter_var() Filters a variable with a specified filter Filter Constants FILTER_VALIDATE_BOOLEAN Validates a boolean FILTER_VALIDATE_EMAIL Certifies an e-mail address FILTER_VALIDATE_FLOAT Confirms a float FILTER_VALIDATE_INT Verifies an integer WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​29
  • 31. FILTER_VALIDATE_IP Validates an IP address FILTER_VALIDATE_REGEXP Confirms a regular expression FILTER_VALIDATE_URL Validates a URL FILTER_SANITIZE_EMAIL Removes all illegal characters from an e-mail address FILTER_SANITIZE_ENCODED Removes/Encodes special characters FILTER_SANITIZE_MAGIC_QUOTES Applies addslashes() FILTER_SANITIZE_NUMBER_FLOAT Removes all characters, except digits, +- and .,eE FILTER_SANITIZE_NUMBER_INT Gets rid of all characters except digits and + – FILTER_SANITIZE_SPECIAL_CHARS Removes special characters FILTER_SANITIZE_FULL_SPECIAL_CHARS Converts special characters to HTML entities FILTER_SANITIZE_STRING Removes tags/special characters from a string, alternative: FILTER_SANITIZE_STRIPPED FILTER_SANITIZE_URL Rids all illegal characters from a URL FILTER_UNSAFE_RAW Do nothing, optionally strip/encode special characters FILTER_CALLBACK Call a user-defined function to filter data WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​30
  • 32. HTTP FUNCTIONS IN PHP HTTP Functions header() Sends a raw HTTP header to the browser headers_list() A list of response headers ready to send (or already sent) headers_sent() Checks if and where the HTTP headers have been sent setcookie() Defines a cookie to be sent along with the rest of the HTTP headers setrawcookie() Defines a cookie (without URL encoding) to be sent along WORKING WITH MYSQL MySQL Functions mysqli_affected_rows() The number of affected rows in the previous MySQL operation mysqli_autocommit() Turn auto-committing database modifications on or off mysqli_change_user() Changes the user of the specified database connection mysqli_character_set_name() The default character set for the database connection mysqli_close() Closes an open database connection mysqli_commit() Commits the current transaction WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​31
  • 33. mysqli_connect_errno() The error code from the last connection error mysqli_connect_error() The error description from the last connection error mysqli_connect() Opens a new connection to the MySQL server mysqli_data_seek() Moves the result pointer to an arbitrary row in the result set mysqli_debug() Performs debugging operations mysqli_dump_debug_info() Dumps debugging information into a log mysqli_errno() The last error code for the most recent function call mysqli_error_list() A list of errors for the most recent function call mysqli_error() The last error description for the most recent function call mysqli_fetch_all() Fetches all result rows as an array mysqli_fetch_array() Fetches a result row as an associative, a numeric array, or both mysqli_fetch_assoc() Fetches a result row as an associative array mysqli_fetch_field_direct() Metadata for a single field as an object mysqli_fetch_field() The next field in the result set as an object WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​32
  • 34. mysqli_fetch_fields() An array of objects that represent the fields in a result set mysqli_fetch_lengths() The lengths of the columns of the current row in the result set mysqli_fetch_object() The current row of a result set as an object mysqli_fetch_row() Fetches one row from a result set and returns it as an enumerated array mysqli_field_count() The number of columns for the most recent query mysqli_field_seek() Sets the field cursor to the given field offset mysqli_field_tell() The position of the field cursor mysqli_free_result() Frees the memory associated with a result mysqli_get_charset() A character set object mysqli_get_client_info() The MySQL client library version mysqli_get_client_stats() Returns client per-process statistics mysqli_get_client_version() The MySQL client library version as an integer mysqli_get_connection_stats() Statistics about the client connection mysqli_get_host_info() The MySQL server hostname and the connection type WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​33
  • 35. mysqli_get_proto_info() The MySQL protocol version mysqli_get_server_info() Returns the MySQL server version mysqli_get_server_version() The MySQL server version as an integer mysqli_info() Returns information about the most recently executed query mysqli_init() Initializes MySQLi and returns a resource for use with mysqli_real_connect() mysqli_insert_id() Returns the auto-generated ID used in the last query mysqli_kill() Asks the server to kill a MySQL thread mysqli_more_results() Checks if there are more results from a multi query mysqli_multi_query() Performs one or more queries on the database mysqli_next_result() Prepares the next result set from mysqli_multi_query() mysqli_num_fields() The number of fields in a result set mysqli_num_rows() The number of rows in a result set mysqli_options() Sets extra connect options and affect behavior for a connection mysqli_ping() Pings a server connection or tries to reconnect if it has gone down WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​34
  • 36. mysqli_prepare() Prepares an SQL statement for execution mysqli_query() Performs a query against the database mysqli_real_connect() Opens a new connection to the MySQL server mysqli_real_escape_string() Escapes special characters in a string for use in an SQL statement mysqli_real_query() Executes an SQL query mysqli_reap_async_query() Returns the result from async query mysqli_refresh() Refreshes tables or caches or resets the replication server information mysqli_rollback() Rolls back the current transaction for the database mysqli_select_db() Changes the default database for the connection mysqli_set_charset() Sets the default client character set mysqli_set_local_infile_default() Unsets a user-defined handler for the LOAD LOCAL INFILE command mysqli_set_local_infile_handler() Sets a callback function for the LOAD DATA LOCAL INFILE command mysqli_sqlstate() Returns the SQLSTATE error code for the last MySQL operation mysqli_ssl_set() Establishes secure connections using SSL WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​35
  • 37. mysqli_stat() The current system status mysqli_stmt_init() Initializes a statement and returns an object for use with mysqli_stmt_prepare() mysqli_store_result() Transfers a result set from the last query mysqli_thread_id() The thread ID for the current connection mysqli_thread_safe() Returns if the client library is compiled as thread-safe mysqli_use_result() Initiates the retrieval of a result set from the last query executed using the mysqli_real_query() mysqli_warning_count() The number of warnings from the last query in the connection DATE AND TIME Date/Time Functions checkdate() Checks the validity of a Gregorian date date_add() Adds a number of days, months, years, hours, minutes and seconds to a date object date_create_from_format() Returns a formatted DateTime object date_create() Creates a new DateTime object date_date_set() Sets a new date WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​36
  • 38. date_default_timezone_get() Returns the default timezone used by all functions date_default_timezone_set() Sets the default timezone date_diff() Calculates the difference between two dates date_format() Returns a date formatted according to a specific format date_get_last_errors() Returns warnings or errors found in a date string date_interval_create_from_date_string() Sets up a DateInterval from relative parts of a string date_interval_format() Formats an interval date_isodate_set() Sets a date according to ISO 8601 standards date_modify() Modifies the timestamp date_offset_get() Returns the offset of the timezone date_parse_from_format() Returns an array with detailed information about a specified date, according to a specified format date_parse() Returns an array with detailed information about a specified date date_sub() Subtracts days, months, years, hours, minutes and seconds from a date date_sun_info() Returns an array containing information about sunset/sunrise and twilight begin/end for a specified day and location WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​37
  • 39. date_sunrise() The sunrise time for a specified day and location date_sunset() The sunset time for a specified day and location date_time_set() Sets the time date_timestamp_get() Returns the Unix timestamp date_timestamp_set() Sets the date and time based on a Unix timestamp date_timezone_get() Returns the time zone of a given DateTime object date_timezone_set() Sets the time zone for a DateTime object date() Formats a local date and time getdate() Date/time information of a timestamp or the current local date/time gettimeofday() The current time gmdate() Formats a GMT/UTC date and time gmmktime() The Unix timestamp for a GMT date gmstrftime() Formats a GMT/UTC date and time according to locale settings idate() Formats a local time/date as an integer WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​38
  • 40. localtime() The local time microtime() The current Unix timestamp with microseconds mktime() The Unix timestamp for a date strftime() Formats a local time and/or date according to locale settings strptime() Parses a time/date generated with strftime() strtotime() Transforms an English textual DateTime into a Unix timestamp time() The current time as a Unix timestamp timezone_abbreviations_list() Returns an array containing dst, offset, and the timezone name timezone_identifiers_list() An indexed array with all timezone identifiers timezone_location_get() Location information for a specified timezone timezone_name_from_abbr() Returns the timezone name from an abbreviation timezone_name_get() The name of the timezone timezone_offset_get() The timezone offset from GMT timezone_open() Creates a new DateTimeZone object WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​39
  • 41. timezone_transitions_get() Returns all transitions for the timezone timezone_version_get() Returns the version of the timezonedb Date and Time Formatting d — 01 to 31 j — 1 to 31 D — Mon through Sun l — Sunday through Saturday N — 1 (for Mon) through 7 (for Sat) w — 0 (for Sun) through 6 (for Sat) m — Months, 01 through 12 n — Months, 1 through 12 F — January through December M — Jan through Dec Y — Four digits year (e.g. 2018) y — Two digits year (e.g. 18) L — Defines whether it’s a leap year (1 or 0) a — am and pm A — AM and PM g — Hours 1 through 12 h — Hours 01 through 12 G — Hours 0 through 23 H — Hours 00 through 23 i — Minutes 00 to 59 s — Seconds 00 to 59 PHP ERRORS Error Functions debug_backtrace() Used to generate a backtrace debug_print_backtrace() Prints a backtrace error_get_last() Gets the last error that occurred WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​40
  • 42. error_log() Sends an error message to the web server’s log, a file or a mail account error_reporting() Specifies which PHP errors are reported restore_error_handler() Reverts to the previous error handler function restore_exception_handler() Goes back to the previous exception handler set_error_handler() Sets a user-defined function to handle script errors set_exception_handler() Sets an exception handler function defined by the user trigger_error() Generates a user-level error message, you can also use user_error() Error Constants E_ERROR Fatal run-time errors that cause the halting of the script and can’t be recovered from E_WARNING Non-fatal run-time errors, execution of the script continues E_PARSE Compile-time parse errors, should only be generated by the parser E_NOTICE Run-time notices that indicate a possible error E_CORE_ERROR Fatal errors at PHP initialization, like an E_ERROR in PHP core E_CORE_WARNING Non-fatal errors at PHP startup, similar to E_WARNING but in PHP core WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​41
  • 43. E_COMPILE_ERROR Fatal compile-time errors generated by the Zend Scripting Engine E_COMPILE_WARNING Non-fatal compile-time errors by the Zend Scripting Engine E_USER_ERROR Fatal user-generated error, set by the programmer using trigger_error() E_USER_WARNING Non-fatal user-generated warning E_USER_NOTICE User-generated notice by trigger_error() E_STRICT Suggestions by PHP to improve your code (needs to be enabled) E_RECOVERABLE_ERROR Catchable fatal error caught by a user-defined handle E_DEPRECATED Enable this to receive warnings about a code which is not future-proof E_USER_DEPRECATED User-generated warning for deprecated code E_ALL All errors and warnings except E_STRICT WebsiteSetup.org - Beginner’s PHP Cheat Sheet ​ ​42