PHP - Getting the index of a element from a array

Question

How can I get the current element number when I'm traversing a array?

I know about count(), but I was hoping there's a built-in function for getting the current field index too, without having to add a extra counter variable.

like this:

foreach($array as $key => value)
  if(index($key) == count($array) ....

$key is a string in my case. anyway I was just wondering if there's a php function that can get the field index. if not, I'll just use a $i counter... — Alex, Sep 21 '10 at 21:33
In the case of an array where the key does not match the index of the array element, I believe Alex would like to obtain the current index. E.g.: `a => apples, b => bananas`: then `index(b)` would return `1`. — Paul Lammertsma, Sep 21 '10 at 21:34
field index == key. it's the same things. And no, there is no way to get item's *position.* — Your Common Sense, Sep 21 '10 at 21:40

score 59 · Accepted Answer · answered Sep 21 '10 at 21:37

59

You should use the key() function.

key($array)

should return the current key.

If you need the position of the current key:

array_search($key, array_keys($array));

answered Sep 21 '10 at 21:37

Zahymaka

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the OP wants a position, not a key. No need to get a kay as it;a already assigned to $key variable – Your Common Sense Sep 21 '10 at 21:38
1

+1 Good answer, I would just like to point out to Alex that adding a counter would be more efficient that searching the array each time though. – Gazler Sep 21 '10 at 21:44
1

so there's no index-like function. thanks :) I'll just use a counter – Alex Sep 21 '10 at 21:47
3

I'd dovnvote it as it's seems way overkill to me. 2 additional loops over whole array per iteration! – Your Common Sense Sep 21 '10 at 21:50

score 13 · Answer 2 · answered Sep 21 '10 at 21:40

PHP arrays are both integer-indexed and string-indexed. You can even mix them:

array('red', 'green', 'white', 'color3'=>'blue', 3=>'yellow');

What do you want the index to be for the value 'blue'? Is it 3? But that's actually the index of the value 'yellow', so that would be an ambiguity.

Another solution for you is to coerce the array to an integer-indexed list of values.

foreach (array_values($array) as $i => $value) {
  echo "$i: $value\n";
}

Output:

0: red
1: green
2: white
3: blue
4: yellow

score 5 · Answer 3 · answered Sep 21 '10 at 21:35

5

foreach() {
    $i++;
    if(index($key) == $i){}
    //
}

answered Sep 21 '10 at 21:35

Galen

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he said without having to add a extra counter variable – rideon88 Sep 21 '10 at 21:37

score 0 · Answer 4 · answered Jan 12 '16 at 11:21

function Index($index) {
    $Count = count($YOUR_ARRAY);
    if ($index <= $Count) {
        $Keys = array_keys($YOUR_ARRAY);
        $Value = array_values($YOUR_ARRAY);
        return $Keys[$index] . ' = ' . $Value[$index];
    } else {
        return "Out of the ring";
    }
}

echo 'Index : ' . Index(0);

Replace the ( $YOUR_ARRAY )

score -1 · Answer 5 · answered Jan 27 '20 at 17:15

I recently had to figure this out for myself and ended up on a solution inspired by @Zahymaka 's answer, but solving the 2x looping of the array.

What you can do is create an array with all your keys, in the order they exist, and then loop through that.

        $keys=array_keys($items);
        foreach($keys as $index=>$key){
                    echo "position: $index".PHP_EOL."item: ".PHP_EOL;
                    var_dump($items[$key]);
                    ...
        }

PS: I know this is very late to the party, but since I found myself searching for this, maybe this could be helpful to someone else

Your Common Sense · Answer 6 · 2010-09-21T21:44:41.007

-2

There is no way to get a position which you really want.
For associative array, to determine last iteration you can use already mentioned counter variable, or determine last item's key first:

end($array);
$last = key($array);
foreach($array as $key => value)
  if($key == $last) ....

edited Sep 21 '10 at 21:44

answered Sep 21 '10 at 21:36

Your Common Sense

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score -2 · Answer 7 · answered Sep 21 '10 at 21:41

an array does not contain index when elements are associative. An array in php can contain mixed values like this:

$var = array("apple", "banana", "foo" => "grape", "carrot", "bar" => "donkey");   
print_r($var);

Gives you:

Array
(
    [0] => apple
    [1] => banana
    [foo] => grape
    [2] => carrot
    [bar] => donkey
)

What are you trying to achieve since you need the index value in an associative array?

PHP - Getting the index of a element from a array

7 Answers7

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