Web app development_php_04

hasen@microcis.net July 03, 2013Hassen poreya
Trainer, Cresco Solution
Afghanistan Workforce
Development Program
PHP
Hypertext Pre-Processor

PHP
 PHP is a recursive acronym that stands for:
 PHP: Hypertext Preprocessor
 Hypertext :
 PHP is used to generate HTML pages.
 Preprocessor:
 The PHP code is processed before delivering HTML
content to the user.

PHP Tags
 Short tags
<?
?>
 Standard tags
<?php
?>
 XML compatible tags
<SCRIPT LANGUAGE="php">
</SCRIPT>

PHP Comments
 Single line comments
//this is a comment
#this is also a comment
 Multiple line comments
/*this is
a multiple line
comment
*/

A Simple PHP code
<html>
<head>
<title>My First PHP Script</title>
</head>
<body>
<?php
echo “Hello World!”;
?>
</body>
</html>

Language Basics – Semicolons
 Semicolons are used to separate different
statements.
<?php
echo “Hello World!”;
echo “Hi”;
?>
 Optional semicolons are coming after } but it’s
required to put a semicolon before }
if($day==“Monday”){
echo “Today is:”$day; //required semicolons here
}; //optional semicolons here

Language Basics – Variables Name
 Variables in PHP starts with $
 Case sensitive
$user_name and $User_Name (Different!!!)
 Valid variable names
$name
$day_of_month
$LastName
$_password
 Invalid variable names
$user name
$|
$5and10

Language Basics – Conventions
 Case sensitive
 Function names
 Class names
 Keywords
 You can not name your variables, functions, classes,
constants the same as a keyword.
 Constants -- Unchangeable value
 Does not start with $
 Using define()you can have a constant.
define(CONST', “A constant!");
echo CONST;

Data Types
 Scalar (Single value)
 Integers
 Floating-point numbers
 Boolean
 Strings
 Compound (Collections)
 Arrays
 Objects
 Special types
 Resource
 NULL

Integers
 Range [-2,147,483,648 to 2,147,483,647]
 Decimal
e.g. 2008
-123
 Octal numbers: a leading 0 and a sequence of digits
0-7
e.g. +0123
 Hexadecimal numbers: begin with 0x, followed by a
sequence of digits (0-9) or letters (A-F).
e.g. 0xFF
0x10

Floating-point Numbers
 Point (Decimal-point, floating-point)
 15 digits of accuracy
e.g.
0.61829384258
12.5

Testing a Data type
 is_int() or is_integer()
 Test, whether a value is an integer.
 is_float() or is_real()
 Test, whether a value is floating-point number.
 Return 1 if true, and 0 if false
<?php
$num=15;
$num2=4.5;
echo “$num is integer?”.is_int($num);
echo “<br> $num is float?”.is_float($num);
?>

Strings
 Strings are collections of textual data.
 e.g, “Microcis Software Solutions” or “Hello World!”
 Double quote VS single quote
 Double quotes expand the variables.
 Single quotes does not.
<?php
$a=“microcis”;
$b=„software‟;
$single=„single quote: $a‟;
double=“double quote: $b”
echo $single.“<br>”;
echo $double.“<br>”;
?>

NULL
 The special NULL value represents that a variable
has no value!
<?php
$var=NULL;
echo “$var is Null?”.is_null($var);
?>
 Use is_null() function whether a variable is
NULL.

Boolean
 A Boolean can be either TRUE or FALSE.
 The following values are considered FALSE
 The boolean(FALSE);
 The integer 0
 The float 0.0
 The empty string or string “0”
 The special type NULL
 An array with no elements
 An object with no value or functions

Boolean
 Every other value is considered as TRUE.
 -1 is considered TRUE, like any other non-zero number.
 Use is_bool() function to test whether a value
return true or false.
 Note: “something” is a string, not boolean; but it is
considered as boolean true.

Arrays
 Array is series of objects which all have the same size
and type.
 Each object in an array is called an array element.
 A group of values
<?php
$city[0]=“Herat”;
$city[1]=“Kabul”;
$city[2]=“Mazar”;
?>
 You can also create an array using array()
$color=array(“Red”, “Green”, “Blue”);
print “$city[0] is $color[1]”;

Types of Arrays
 Associative arrays
 Numeric arrays
 Multidimensional arrays

Numeric Arrays
 A numeric array stores each element with a
numeric ID key.
$names = array(“Ahmad",“Mahmood",“Bob");
 In this example the ID key is automatically
assigned.

Associative Arrays
 With Associative arrays we can use strings as keys
and assign values to them.
$ages = array(“Ahmad"=>32, “Mahmood"=>30,
“Bob"=>34);
print_r($ages);

Multidimensional Arrays
 Each element in the main array can be an array.
And each element in the sub-array can also be an
array, and so on.
$countries = array(
“Afghanistan"=>array(“Herat",
“Kabul", “Mazar"), “Iran"=>array (
“Tehran" ), “Pakistan"=>array (
“Islamabad", “Peshavor", “Kerachi"
) );

print_r() function
 You can see the structure and values of any array
by using print_r() function.
print_r($fruit_basket);
 Output:
Array
(
[red] => apple
[orange] => orange
[yellow] => banana
[green] => pear
)

array_rand() function
 Returns a random key from an array, or it returns an
array of random keys.
 If you specify that, the function should return more
than one key.
array_rand(array,number);
<?php
$name=array("a"=>“Ahmad","b"=>“Bah
ram",“s"=>“Sina");
print_r(array_rand($name,1));
?>
 The output of the code above could be: b

Shuffle() function
 The shuffle() function randomizes the order
of the elements in the array.
shuffle(array);
<?php
$colors = array(“r" => “red", "b"
=> “blue", “g" => “green");
shuffle($colors);
print_r($colors);
?>
Output: Array ( [0] => blue [1] => green [2] => red )

str_split() function
 Splits a string into an array.
str_split(string,length)
 Parameters
 String: Specifies the string to split
 Length: Optional and specifies the length of each array
element. Default is 1
<?php
print_r(str_split("Hello"));
?>

str_split() function
 The output of the code above will be:
Array
(
[0] => H
[1] => e
[2] => l
[3] => l
[4] => o
)

hasen@microcis.net July 03, 2013Hassen poreya
Trainer, Cresco Solution
Any Questions!

Web app development_php_04

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