isset v 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($y)){
echo 'y is set';
}
/**
* This will NOT echo out 'y is set'
*/
php zjistit, jestli undefined
if (isset($variable)) { /* do something */ };
Nedefinovaná proměnná uvnitř funkce php
$myId = 0;
function run(){
global $myId;
echo $myId;
}
php nedefinováno
if (isset($variable)) { /* do something */ };