php Undefined
snippet in php

undefined variable inside function php

user8178

$myId = 0;
function run(){
  global $myId;
	echo $myId;
}

isset in php

user4041

/**
 * 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'
 */

php Undefined

user9567

if (isset($variable)) { /* do something */ };