Getting the values key in an array

Question

I'm experiencing som difficulties to check if a key exists in an array or not. What I want to do is:

if(array_key_exists('hello',$myArray)) {
   do stuff;
}

or:

if(isset($myArray['hello'])) {
   do stuff;
}

But I think I am doing this in the wrong way, or something like that. I use variables as my keynames, so when I set the array key and value I do it something like this:

//myArray = an array with some random words
foreach($myArray as $item) {
    if($item == 'hello') {
        //Create a new array to put stuff in
        $myNewArray[$item] = 1;
    }
}

However, if I later want to check if if the key 'hello' exists (using a variable again, in an array, just for the sake of it):

$item[0] = 'hello';
$item[1] = 'hello again sir';

if(array_key_exists($item[0], $myNewArray)) {
    echo 'The key exists!';
} else {
    echo 'The key does not exists';
}

//Output: The key does not exists

So – any ideas on what I am doing wrong? Any good ways to approach this problem? And please note; I've already tried to use to put the needle between single quotation marks.

Update: Some output using var_dump() in my real code - http://pastebin.com/5N1ZWC9f - Still not really getting why it doesn't work as it should?

As some have pointed out - ofcourse it should be "$myNewArray", my mistake. This is however only example code – the problem still exists. — Marcus Olsson, Aug 31 '11 at 11:07
Take also a look here: http://stackoverflow.com/questions/6576247/how-to-avoid-undefined-index/6576252#6576252, it explain differences between `isset` and `array_key_exists` — Fabio, Aug 31 '11 at 11:11
are you sure `$item` is an array? try putting `$item = Array()` before actually assigning anything to it — Quamis, Aug 31 '11 at 11:50
At first look everything is ok. You're doing good :) There must be some detail which makes your code fail... Can you provide whole code ? — Roman Pietrzak, Aug 31 '11 at 10:58

score 0 · Answer 1 · answered Aug 31 '11 at 10:58

0

The function var_dump() can always give you good insight into what exactly is in your array. That should help debugging your code. As for your example code, I think the problem is you're checking $myArray where I think you want to be checking $myNewArray;

if(array_key_exists($item[0],$myNewArray)) {
    echo 'The key exists!';
} else {
    echo 'The key does not exists';
}

answered Aug 31 '11 at 10:58

Rijk

11,032
3
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Ofcourse – my bad =) This is however only code that I wrote for this example, the problem still persists. – Marcus Olsson Aug 31 '11 at 11:08
Well, than I don't know what's going wrong, your code looks good. Have you tried using `var_dump()` already, to find out what's in the array? – Rijk Aug 31 '11 at 11:09

score 0 · Answer 2 · answered Aug 31 '11 at 10:58

In your last part:

if(array_key_exists($item[0],$myArray)) {
    echo 'The key exists!';
} else {
    echo 'The key does not exists';
}

You are searching in $myArray, not in $myNewArray. But that might not be your actual code. What do you see as keys in $myNewArray if you do:

print_r($myNewArray);

If 'hello' is there as key, then the script should echo 'The key exists!'

score 0 · Answer 3 · answered Aug 31 '11 at 11:01

0

I think you are checking a key pair value. So 'Hello' is the value and '0' is the key. Try setting up the array as:

$myArray = ('hello' => 'This is the value');

if (array_key_exists('hello',$myArray) {
echo 'I exist!';
}

Try that.

answered Aug 31 '11 at 11:01

mashdup

875
7
18

score 0 · Accepted Answer · answered Oct 08 '11 at 12:10

0

Found out that the value wasn't a string, but an SimpleXML object, which made so that I couldn't compare them (naturally...). Beginners mistake from my side.

answered Oct 08 '11 at 12:10

Marcus Olsson

2,485
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35

Getting the values key in an array

4 Answers4