PHP - Checking if array index exist or is null

Question

Is there a way to check if an array index exists or is null? isset() doesn't tell you whether the index doesn't exist or exists but is null. If I do : isset($array[$index]) || is_null($array[$index]) it won't work because if the index doesn't exist is_null will crash.

How can I check this please? Also is there a way to check only if something exist, no matter if it is set to null or not?

Wouldn't the same if statements in a nested if structure work fine? — christopher, Mar 09 '13 at 11:46

score 47 · Accepted Answer · edited Nov 07 '17 at 09:27

47

The function array_key_exists() can do that, and property_exists() for objects, plus what Vineet1982 said. Thanks for your help.

edited Nov 07 '17 at 09:27

akinuri

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answered Mar 09 '13 at 12:04

Virus721

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1

Using array_key_exists() on objects is deprecated. – Asish Dec 30 '20 at 10:12
1

@Asish No one said one should do that. And this question is 8 years old, so obviously things evolve. – Virus721 Dec 31 '20 at 13:28
Yes. That is why I mentioned it. And it didn't work in my case. So,.. – Asish Jan 01 '21 at 16:02
This answer is still valid in 2022. array_key_exists for arrays (not objects), property_exists for objects. – Dave S Mar 31 '22 at 18:32

score 22 · Answer 2 · answered Mar 09 '13 at 12:02

22

This is the very good question and you can use get_defined_vars() for this:

$foo = NULL;
$a = get_defined_vars();

if (array_key_exists('def', $a)) {
   // Should evaluate to FALSE
 }; 

if (array_key_exists('foo', $a)) {
   // Should evaluate to TRUE
};

This will solve your problem

answered Mar 09 '13 at 12:02

Vineet1982

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Ok but add the array_key_exist thing in it then – Virus721 Mar 09 '13 at 12:20

Teerath Kumar · Answer 3 · 2023-02-05T20:02:09.933

11

Simplest defined in: http://php.net/manual/en/function.array-key-exists.php

<?php
$array=array('raja'=>'value', 'john'=>'value2');
$var='raja';
echo array_key_exists($var, $array);
?>

OR

<?php
$array=array('raja'=>'value', 'john'=>'value2');

echo isset($array['raja']) ? "exists" : "does not exist";
?>
//Output: exists

edited Feb 05 '23 at 20:02

answered Jul 23 '15 at 07:46

Teerath Kumar

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PHP - Checking if array index exist or is null

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