String
strlen( ) for calculate length of string
strtoupper ( ) for make Uppercase the string
strtolower ( ) for make Lowercase the string
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Array
https://www.php.net/en/ref.array
$list = [1,3,4,5]
Part of the array
$list2 = [2,4];
$string = [2,$list2];
$combine = in_array($list2,$string);
if ($combine) {
echo "equal" . "<br>";
}
//--Result
equal