use of isset in php code example

Example 1: isset in php

/**
 * Returns a bool (true or false)
 */
isset($x);
/**
 * Examples
 */
$x = 'myValue';
if(isset($x)){
	echo 'x is set';
}
/**
 * this will echo out 'x is set'
 */


$x = null;
if(isset($x)){
	echo 'x is set';
}
/**
 * This will NOT echo out 'x is set'
 */


if(isset($y)){
 	echo 'y is set'; 
}
/**
 * This will NOT echo out 'y is set'
 */

Example 2: what is isset in php

The isset() function checks whether a variable is set, which means that it has to be declared and is not NULL.

This function returns true if the variable exists and is not NULL, otherwise it returns false.

Example 3: php if isset

if (isset(true)) {
}