How can I check if a value exists in my array?

Question

I'm quite new to PHP... I am trying to check if a value exists in my $Session array and then display the content according to that but it is always showing 'Match not found' even when I know the value does exist in the array.

This is a print_r of my array:

Array (
    [0] => Array ( 
        [0] => SIEMENS 
        [1] => 523-096-32 
        [2] => 1
        [3] => New 
    ) 
)

When I do:

$array = $_SESSION['arr'];

if( in_array( "523-096-32" , $array ) ){
    echo "Match found";
}else{
    echo "Match not found";
}

The result is "Match not found".

I have also tried replacing in_array with array_key_exists but I'm having the same result.

My question is: where am I going wrong and how can I fix it to display "Match found"? Any help would be greatly appreciated.

`in_array` only checks one level deep, your value is in a nested array so you'd need to do `in_array( "523-096-32" , $array[0] )` to find it — naththedeveloper, Nov 30 '18 at 15:41
Possible duplicate of [in\_array() and multidimensional array](https://stackoverflow.com/questions/4128323/in-array-and-multidimensional-array) — user3783243, Nov 30 '18 at 15:49
array_key_exists is for key not for value. [documentation](http://php.net/manual/en/function.array-key-exists.php) — Alberto Moro, Nov 30 '18 at 15:52

Don't Panic · Answer 1 · 2018-11-30T16:45:05.780

Using in_array("523-096-32", $array[0]) as the comment on your question indicates will work, but it may not be the best solution depending on what $_SESSION['arr'] is supposed to do. The best way to check for that value depends on whether or not $_SESSION['arr'] is supposed to be a multidimensional array.

It looks like the array inside $_SESSION['arr'] is a set of values representing a single item. If $_SESSION['arr'] is meant to hold a group of those items, although there's only one in the example you showed, looking in $array[0] will only check the first item. Instead you can iterate it and check each item for that value until you find it (or not).

$found = false;
foreach ($_SESSION['arr'] as $item) {
    if ($item[1] === "523-096-32") {
        $found = true;
        break;
    }
}
echo $found ? 'Match found' : 'Match not found';

If the items inside $_SESSION['arr'] aren't consistently structured, referring to $item[1] won't be accurate and you should use in_array instead.

if (in_array("523-096-32", $item)) { ...

If $_SESSION['arr'] is only one level deep, you shouldn't need to use a recursive function to find a match.

On the other hand, if $_SESSION['arr'] is only meant to be one array, rather than an array with another array in it like you have, you probably assigned it incorrectly, like

$_SESSION['arr'][] = ['SIEMENS', '523-096-32', '1', 'New'];

instead of

$_SESSION['arr'] = ['SIEMENS', '523-096-32', '1', 'New'];

If you assign it directly like the second example here, using in_array like you tried to do will work.

Hmm, whoever downvoted, is there something incorrect or inaccurate in the answer, or did you just think the question should be closed instead of answered? If it's the second thing I can understand why you wouldn't want to say anything, but if not I'd like to know if I made a mistake. — Don't Panic, Nov 30 '18 at 16:54
No offense, but don't see how this could help OP. You are replacing the nice and short in_array() with a inflexible foreach-loop, pointing to a fixed array index. This kinda make the simple "bug" more complicated than it is, doesn't it? Cheers! (I'm the downvoter, sorry, slow in writing... ;)) So, to be "constructive": I would stick with the in_array solution and maybe offer an recursive function. This would help in most possible cases. — n.r., Nov 30 '18 at 16:55
No offense taken, thanks for commenting. I just thought that based on the values in the inner array it seemed likely that `$_SESSION['arr'][1]` etc. could also exist at some point, and if that was the case, a single `in_array` would no longer suffice. And if that _wasn't_ the case, it shouldn't have been multidimensional in the first place and that should be fixed instead of looking at the pointless `[0]`. Then again, I do have a tendency to to overthink things :-) — Don't Panic, Nov 30 '18 at 17:02
But I'm not arguing with your vote. I appreciate that there are different opinions on things. — Don't Panic, Nov 30 '18 at 17:04

How can I check if a value exists in my array?

1 Answers1