w3resource

PHP: unset() function

Description

The unset() function destroys a given variable.

Version:

(PHP 4 and above)

Syntax:

unset (var1, var2.... )

Parameters:

Name Description Required /
Optional
Type
var1 The variable to be unset. Required Mixed*
var2 Another variable to be unset Optional Mixed*

*Mixed: Mixed indicates that a parameter may accept multiple (but not necessarily all) types.

Return value:

No value is returned.

Example - 1:

<?php
$xyz='w3resource.com';
echo 'Before using unset() the value of $xys is : '. $xyz.'<br>';
unset($xyz);
echo 'After using unset() the value of $xys is : '. $xyz;
?>

Output :

Before using unset() the value of $xys is : w3resource.com
After   using unset() the value of $xys is : 

View the example in the browser

Practice here online :

Example - 2 :

<?php
function destroy_variable()
{
unset($GLOBALS['w3resource']);
}
$w3resource='Php Tutorial';
destroy_variable();
echo $w3resource;
?> 
    

View the example in the browser

See also

PHP Function Reference

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PHP: Tips of the Day

PHP - how to create a newline character?

Only double quoted strings interpret the escape sequences \r and \n as '0x0D' and '0x0A' respectively, so you want:

"\r\n"

Single quoted strings, on the other hand, only know the escape sequences \\ and \'.

So unless you concatenate the single quoted string with a line break generated elsewhere (e. g., using double quoted string "\r\n" or using chr function chr(0x0D).chr(0x0A)), the only other way to have a line break within a single quoted string is to literally type it with your editor:

$s = 'some text before the line break
some text after';

Make sure to check your editor for its line break settings if you require some specific character sequence (\r\n for example).

Ref : https://bit.ly/3hcyege