php is set – How to check whether a variable is set or not in PHP?

php is set used to determine that a variable is set or not. The isset() function is an inbuilt function in PHP which checks whether a variable is set and is not NULL.

php is set – isset() and !empty() function in PHP

check whether a variable is set or not in PHP – Use the PHP isset() function

PHP isset() function syntax

isset(“variable”);

PHP isset() – Check If Variable Is Set

Use the PHP isset() function

";
 
$str2 = 'Welcome TO Pakainfo.com!';
if(isset($str2)){
    echo 'This slogen is displayed, because the $str2 is set.';
}
echo "
";
 
// Unset the striable
unset($str2);
 
if(isset($str2)){
    echo 'This slogen is displayed, because the $str2 is set.';
} else{
    echo 'This slogen is displayed, because the $str2 is not set.';
}
echo "
";
 
$str3 = NULL;
if(isset($str3)){
    echo 'This slogen is displayed, because the $str3 is set.';
} else{
    echo 'This slogen is displayed, because the $str3 is not set.';
}
?>

PHP isset() Example

//The output is :
boolean true

Checking if a Cookie is Set

Use the PHP isset() function upon the superglobal $_COOKIE variable to check if a cookie is set.

Example:

if (isset($_COOKIE['member'])) {

    echo 'Member is ' . $_COOKIE['member'];
else {
    echo 'Member is not sign in';
}

// PHP 7.0+
echo 'Member is ' . $_COOKIE['member'] ?? 'Member is not sign in'; 

I hope you get an idea about php is set.
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