Programming Basics - array, loops, funcitons

TRIVUz Academy

PF03
Class Id:

Programming Fundamentals
MS Alam TRIVUz
Founder, TRIVUz Network
TRIVUz Academy

TRIVUz Academy

Recap PF01 & PF02

TRIVUz Academy

Recap
We Define Computer & Programming

Programming Process

Programming Language

Inputs & Outputs

Define Logical Processing

Variables

Data Types

Define Conditional Statement
If… Then… Else…
TRIVUz Academy PHP Operators

www.trivuzacademy.com

We are going to learn
Variable+

Array

Array Functions

Global Array

Loop

for, do…while, for each

Functions


TRIVUz Academy
www.trivuzacademy.com

Variable+
Array

TRIVUz Academy

Array
What is an Array?
A variable is a storage area holding a number or
text. The problem is, a variable will hold only one
value.

TRIVUz Academy

Array
What is an Array?
A variable is a storage area holding a number or
text. The problem is, a variable will hold only one
value.
An array is a special variable, which can store
multiple values in one single variable.

TRIVUz Academy

Array
What is an Array?
• An array in PHP is a structure which maps keys
(array element names) to values
• The keys can specified explicitly or they can be
omitted
• If keys are omited, integers starting with 0 are
keys
• The value mapped to a key can, itself, be an
array, so we can have nested arrays

TRIVUz Academy

Array
What is an Array?
Variable VS Array

TRIVUz Academy

Array
What is an Array?
Variable VS Array?
In Variable:
<?php

$student = “Farah”;

$student = “Tawhid”;

$student = “Jewel”;

?>

TRIVUz Academy

Array
What is an Array?
Variable VS Array?
In Array:
<?php

$student = array(“Farah”,”Tawhid”,”Jewel”);

?>

TRIVUz Academy

Array
What is an Array?
Variable VS Array?
Array will create Variable index like
$student[0] = “Farah”;

$student[1] = “Tawhid”;

$student[2] = “Jewel”;

TRIVUz Academy

Array
Very simple array and output

Code
<?php

$student = array(“Farah”,”Tawhid”,”Jewel”);

print_r($student);

?>

Output
Array ( [0] => Trivuz [1] => Tawhid [2] => Jewel )

TRIVUz Academy

Array
Echo value from array

Code
<?php

echo $student[0];
echo $student[1];
?>

Output
Farah
Tawhid

TRIVUz Academy

Array
Change Value in Array

Code
<?php
$student[0] = ”Trivuz”;
$student[2] = "Asif Islam”;
print_r($student);
?>

Output
Array ( [0] => Trivuz[1] => Tawhid [2] => Asif Islam )

TRIVUz Academy

Array
Specifying an Array
• A special function is used to specify arrays
array()

• Format of Usage
array([key=>]value, …)

• A key is either a string or a non-negative integer

• A value can be anything

• Format of associative array specification
$ages = array(“Huzaifa”=>22, “Tuhin”=>23)

TRIVUz Academy

Array
Specifying an Array
• Here is another associative (hash) array:
$ages[„Riaydh‟]=“24”;
$ages[„Piash‟]=“21”;

• Implicit indices are integers, starting at 0
$student = array(“Koushik”,”Tafsir”,”Eunus”);

• Here is the same array written differently
$student[0] = “Koushik”;
$student[0] = “Tafsir”;
$student[0] = “Eunus”;

TRIVUz Academy

Array
Specifying an Array
• If and explicit integer index is followed by
implicit indices, they follow on from the highest
previous index
• Here is an array indexed by integers 1,2,3
$student = array(1=>“Avishek”,”Mehedi”,”Masud”);

• Here is an array indexed by integers 1,5,6
$student = array(5=>“Avishek”,1=>”Mehedi”,”Masud”);

• Show output
<?php
print_r($student);
?>

TRIVUz Academy

Array
Specifying an Array
• A two-dimensional hash array
$result = array(“Farah“=>array(“Bangla”=>85,”English”=>78));

echo $result[„Farah‟][„Bangla];
echo $result[„Farah‟][„English‟];

• A two-dimensional ordinary array
$heights = array(10,20,30,40,50),array(100,200));

echo $heights[0][1]; // output : 20
echo $heights[1][1]; // output : 200

• Change a two-dimensional array value
$heights[0][0] = 130;
$heights[0][1] = 140;
print_r($heights); // output : Array ( [0] => Array ( [0] => 130 [1] => 140 ) )

TRIVUz Academy

Array Functions
PHP provides a huge set of array-manipulation functions
 array – Create an array
 array_change_key_case – Returns an array with all string keys
lowercased or uppercased
 array_chunk – Split an array into chunks
 array_count_values – Counts all the values of an array
 array_diff – Computes the difference of arrays
 array_filter – Filters elements of an array using a callback funciton
 array_flip – Flip all the values of an array
 array_fill – Fill and array with values
 array_intersect – Computes the intersection of arrays
 array_key_exists – Checks if the given key or index exists in the
array
 array_keys – Return all the keys of an array

TRIVUz Academy

Array Functions
 array_map – Applies the callback to the elements of the given
arrays
 array_merge – Merge two or more arrays
 array_merge_recursive – Merge two or more arrays recursively
 array_multisort – Sort multiple or multi-dimensional arrays
 array_pad – Pad array to the specified length with a value
 array_pop – Pop the element off the end of array
 array_push – Push one or more elements onto the end of array
 array_rand – Pick one or more random entries out of an array
 array_reverse – Return an array with elements in reverse order
 array_reduce – Iteratively reduce the array to a single value using
a callback function
 array_shift – Shift an element off the beginning of array
 array_slice – Extract a slice of the array
TRIVUz Academy

Array Functions
 array_splice – Remove a portion of the array and replace it with
something else
 array_sum – Calculate the sum of values in an array
 array_unique – Remove duplicate values from an array
 array_unshift – Prepend one or more elements to the beginning of
array
 array_values – Return all the values of an array
 array_walk – Apply a user function to every member of an array
 arsort – Sort an array in reverse order and maintain index
association
 asort – Sort an array and maintain index association
 compact – Create array containing variables and their values
 count – Count element in a variable
 current – Return the current element in an array
TRIVUz Academy

Array Functions
 each – Return the current key and value pair from an array and
advance the array cursor
 end – Set the internal pointer of an array to its last element
 extract – Import variables into the current symbol table from an
array
 in_array – Return TRUE if a value exists in an array
 Array_search – Searches the array for a given value and returns
the corresponding key if successful
 key – Fetch a key from an associative array
 krsort – Sort an array by key
 list – Assign variables as if they were an array
 natsort– Sort an array using a “natural order” algorithm
 pos – Get the current element from an array
 prev – Rewind the internal array pointer
TRIVUz Academy

Array Functions
 range – Create an array containing a range of elements
 reset – Set the internal pointer of an array to its first element
 rsort – Sort an array in reverse order
 shuffle – Shuffle an array
 sizeof – Get the number of elements in variable
 sort – Sort an array
 uasort – Sort an array with a user-defined comparison function
 uksort – Soft an array by keys using a user-defined comparison
function
 usoft– Soft an array by values using a user-defined comparison
function

TRIVUz Academy

Global Array
Global Arrays
 PHP Creates 6 global arrays that contain EGPCS (ENVIRONMENT,
GET, POST, COOKIES and SERVER) information
 PHP also creates a variable called $_REQUEST that contains all the
information in the 6 global arrays
 PHP also creates a variable called $PHP_SELF that contains the
name of the current script (relative to the doc root)
 $_ENV – Contains the values of any environment variables, such as
the browser version
 Eg: $_ENV[HTTP_USER_AGENT]

 $_FILES – Contains information about any files submitted
 $_COOKIES – Contain any cookies submitted as name value pairs
 $_SERVER – Contains useful information about the webserver

TRIVUz Academy

Global Array
$_SERVER Keys
 [DOCUMENT_ROOT]  [SERVER_SOFTWARE]
 [HTTP_*]  [COMSPEC]
 [PHP_SELF]  [GATEWAY_INTERFACE]
 [QUERY_STRING]  [PATHEXT]
 [REMOTE_ADDR]  [PATH]
 [REQUEST_METHOD]  [REMOTE_PORT]
 [REQUEST_URI]  [SERVER_ADDR]
 [SCRIPT_FILENAME]  [SERVER_ADMIN]
 [SCRIPT_NAME]  [SERVER_SIGNATURE]
 [SERVER_PORT]  [SystemRoot]
 [SERVER_PROTOCOL]  [WINDIR]

TRIVUz Academy

Control Structure
Looping

TRIVUz Academy

Control Structure
Looping

 Loops execute a block of code a specified number of
times, or while a specified condition is true.

 PHP loops are control structures and you can use
them the execute a code block more times. It means
you don't have to copy and paste your code many
times in the file just use a right loop statement.

TRIVUz Academy

Control Structure
Looping
A basic example:
<?php
echo " 1 ”;
echo " 2 ”;
echo " 3 ”;
echo " 4 ”;
echo " 5 ”;
?>

TRIVUz Academy

Control Structure
Looping
A basic example:
<?php
echo " 1 ”;
echo " 2 ”;
echo " 3 ”;
echo " 4 ”;
echo " 5 ”;
?>

With a for loop it looks like this:
<?php
for ($i=1; $i <= 5; $i++) {
echo “ $i “;
}
?>
TRIVUz Academy

Control Structure
Looping

 In PHP, we have the following looping statements:
 While
 Do…while
 For
 foreach

TRIVUz Academy

Control Structure
while loop
Syntax

while

TRIVUz Academy

Control Structure
while loop
Syntax

while (condition)

TRIVUz Academy

Control Structure
while loop
Syntax

while (condition)
{
// code to be executed;
}

TRIVUz Academy

Control Structure
while loop
Example

<?php

$i = 1;
while ($i < 5)
{
echo “ I = “ . $i . “ ”;
echo $i++;
}

?>

TRIVUz Academy

Control Structure
while loop
Execution
Code:
<?php
$i = 1;
while ($i < 5)
{
echo “ Value of I is now “ . $i . “ ”;
echo $i++;
}
?>

TRIVUz Academy

Control Structure
while loop
Execution (Loop - 1)
Code:
<?php
$i = 1;
while ($i < 5) // $i is now 1
{
echo $i++; // $i is now 2
}
?>

Output:
Value of I is now 1

TRIVUz Academy

Control Structure
while loop
Code:
<?php
$i = 1;
{
}
?>

Output:
Value of I is now 1
Value of I is now 2

TRIVUz Academy

Control Structure
While Loop
Code:
<?php
$i = 1;
{
}
?>

Output:
Value of I is now 1
Value of I is now 2
Value of I is now 3

TRIVUz Academy

Control Structure
while loop
Code:
<?php
$i = 1;
{
}
?>

Output:
Value of I is now 1
Value of I is now 2
Value of I is now 3
Value of I is now 4

TRIVUz Academy

Control Structure
while loop
Code:
<?php
$i = 1;
{
echo $i++; // not executed
}
// next code to execute
?>
Output:
Value of I is now 1
Value of I is now 2
Value of I is now 3
Value of I is now 4

TRIVUz Academy

Control Structure
do…while loop
Syntax

do {
}
while (condition);

TRIVUz Academy

Control Structure
do…while loop
Example

do {
$i++;
echo “The number is “ . $i . “ ”;
}
while ($i < 5);

TRIVUz Academy

Control Structure
for loop
Syntax

for (init; condition; increment)

{

}

TRIVUz Academy

Control Structure
for loop
Example

for ($i = 1; $i < 5; $++)

{
echo “Current value of I is “ . $i . “ ”;

}

TRIVUz Academy

Control Structure
for each

FOREACH is used in PHP to loop over all elements of an array. The basic
syntax of FOREACH is as follows:
FOREACH ($array_variable as $value)
{
//code to execute
}

or

FOREACH ($array_variable as $key => $value)
{
//code to execute
}

TRIVUz Academy

Control Structure
for each
Simple Syntax

foreach (array_expression as $value)

// statement

foreach (array_expression as $key => $value)

// statement

TRIVUz Academy

Control Structure
for each
Example

<?php

$arr = array(1, 2, 3, 4);

foreach ($arr as &$value) {

$value = $value * 2;

}

// $arr is now array(2, 4, 6, 8)

unset($value); // break the reference with the last element

?>

TRIVUz Academy

Control Structure
for each
Example

<?php
$arr = array("one", "two", "three");
reset($arr);
while (list(, $value) = each($arr)) {
echo "Value: $value n”;
}
foreach ($arr as $value) {
echo "Value: $value n”;
}
?>

TRIVUz Academy

Function

What is function?

How function help programmers?

Types of function

TRIVUz Academy

Function

System Defined Function

User Defined Function

TRIVUz Academy

Function
User-Defined Function

In PHP, functions are defined in the following fashion:

function function_name ([variable [= constant][,…])
{

// any valid PHP code

}

TRIVUz Academy

Function

Example: User-Defined Function to determine a Leap Year

<?php

function is_leapyear ($year = 2011)
{

$is_leap = (!($year % 4) && (($year % 100) || !($year % 400)));

return $is_leap;

}

?>

TRIVUz Academy

Function

Function with user defined argument

function function_name ($arg)
{

// any valid PHP code

}

TRIVUz Academy

Function


<?php
function is_leapyear ($year)
{


return $is_leap;

}

?>

TRIVUz Academy

Function


<?php
function is_leapyear ($year)
{


return $is_leap;

}

?>
Calling the user defined function is_leapyear

Is_leapyer(2008);
Is_leapyer(2011);
TRIVUz Academy

Thank You

MS Alam TRIVUz
Founder,
TRIVUz Academy
trivuz@gmail.com

Programming Basics - array, loops, funcitons

Recommended

More Related Content

What's hot (20)

Viewers also liked (10)

Similar to Programming Basics - array, loops, funcitons (20)

Recently uploaded (20)

Programming Basics - array, loops, funcitons

Editor's Notes