Get foreach numeric index when keys are named

Question

This question is just for fun and out of curiosity.

Edit : My question is different than How to find the foreach index Because $key has already a non-numeric value in my case.

Without having a variable outside a foreach that is increment inside the foreach scope, as the usual $i, is there a way to get the index of an item when $key is already named ?

Exemples :

$myNumericIndexArray = ('foo', 'bar', 'go', 'habs');

foreach($myNumericIndexArray as $key => $value){
    //Here $key will be 0 -> 1 -> 2 -> 3
}

Now, if I have :

$myNamedIndexArray = ('foo' => 'bar', 'go' => 'habs', 'CSGO_bestTeam' => 'fnatic');

foreach($myNamedIndexArray as $key => $value){
    //Here $key will be foo -> go -> CSGO_bestTeam
}

Can I, without having to :

$i=0;
foreach($myNamedIndexArray as $key => $value){
    //Here $key will be foo -> go -> CSGO_bestTeam
    $i++;
}

access the index of a named array. Something declared in the foreach declaration like in a for or a status of $key ?

Have a good one.

No you can't declare a counter variable in the foreach construct. You could do it with a for-loop and just save the keys in an array, which you then can access with the counter variable. — Rizier123, Mar 10 '16 at 17:44
Also: foreach doesn't have its own scope. PHP has function scope and whatever you declare in foreach you can also use outside of it. — Rizier123, Mar 10 '16 at 17:45
@Drudge Yes, basically having a counter on the key when they are treated. Without having to declare a counter outside the scope that is incremented on each iteration. This has no goal, really, just curious if there was neat stuff to do with this — Kevin Gagnon, Mar 10 '16 at 17:47
Possible duplicate of [How to find the foreach index](http://stackoverflow.com/questions/141108/how-to-find-the-foreach-index) — Don't Panic, Mar 10 '16 at 17:49
@Rizier123 I think I just chose my words poorly, as English not being my first language. I meant "between the curly braces". As I understand now, "scope" is more definite than that. Like a class. Just a little misunderstanding on the word. — Kevin Gagnon, Mar 10 '16 at 17:50
@KevinGagnon So you want a numeric index for your associative array inside the foreach loop, without defining or doing anything else outside of the foreach construct? (Which doesn't make much sense, unless it's a little coding challenge for you; Also see: http://stackoverflow.com/q/16959576/3933332 to see what exactly "variable scope" in PHP means) — Rizier123, Mar 10 '16 at 17:53
@Rizier123 Ahh on, like I mentioned it is only for fun and out of curiosity. Getting to know the language better, you know. — Kevin Gagnon, Mar 10 '16 at 18:20
@Don'tPanic : My question is different than the one you linked. See my edit on why. — Kevin Gagnon, Mar 10 '16 at 18:28

Ravindra Bhalothia · Answer 1 · 2016-03-10T18:36:23.147

4

If you really want index array of associative array than try this:

$myNamedIndexArray = ['foo' => 'bar', 'go' => 'habs', 'CSGO_bestTeam' => 'fnatic'];

$keys = array_keys($myNamedIndexArray);
foreach($myNamedIndexArray as $key => $value){
     echo array_search($key, $keys);
}

edited Mar 10 '16 at 18:36

answered Mar 10 '16 at 17:47

Ravindra Bhalothia

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This is exactly what I was looking for. It keeps the named index and gives you the numeric index of the item iterated on. Perfect. Thank you. – Kevin Gagnon Mar 10 '16 at 18:19
1

It works but, why you would want to do an array_keys() and array_search() every loop iteration??? – AbraCadaver Mar 10 '16 at 18:34
Yes Agreed, we can get keys in separate variable. I've updated coded accordingly. – Ravindra Bhalothia Mar 10 '16 at 18:35
1

@RavindraBhalothia I think OP just want the key then why to use array_search again in every loop iteration ? – Drudge Rajen Mar 10 '16 at 18:37
@Drudge : I love to know if there is any other way to do the same. Please let us know. – Ravindra Bhalothia Mar 10 '16 at 18:40
you can check @AbraCadaver or mine answer . – Drudge Rajen Mar 10 '16 at 18:41

score 3 · Answer 2 · answered Mar 10 '16 at 18:00

3

Something like this :

<?php
$myNamedIndexArray = array('foo' => 'bar', 'go' => 'habs', 'CSGO_bestTeam' => 'fnatic');
$numericIndexArray = array_keys($myNamedIndexArray);
foreach($numericIndexArray as $key=>$value){
    echo $key.'</br>'; //here key will be 0 1 2
    echo $value. '</br>';
}

answered Mar 10 '16 at 18:00

Drudge Rajen

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This could work. I went with Ravindra's answer but this covers my question also. Thanks for your time :) – Kevin Gagnon Mar 10 '16 at 18:25
1

Great it works for you . :) . If this answer looks working for you, then please accept the answer so that it can be helpful to others as well. – Drudge Rajen Mar 10 '16 at 18:27

score 3 · Accepted Answer · answered Mar 10 '16 at 18:33

3

I don't know why you would want to do an array_keys() and array_search() every loop iteration. Just build a reference array and you can still foreach() the original:

$positions = array_flip(array_keys($myNamedIndexArray));

foreach($myNamedIndexArray as $key => $value){
    echo "{$key} => {$value} is position {$positions[$key]}\n";
}

answered Mar 10 '16 at 18:33

AbraCadaver

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That works if PHP iterates on an array in the same order that array_keys does. Which is a knowledge I do not have. Is there documentation on this that I could read ? This would become my favourite answer, as it serves the main purpose of the question and it saves CPU cycles. – Kevin Gagnon Mar 10 '16 at 18:46
I'm not sure I understand the question. `array_keys()` assigns the first key to index 0, the second to index 1, etc. `foreach()` resets the array pointer and starts at the first element of the array. The `$positions` array and `$myNamedIndexArray` will always match unless you modify them somehow. Plug any array into this and it works as expected. – AbraCadaver Mar 10 '16 at 18:50
http://stackoverflow.com/questions/4733188/is-foreach-guaranteed-to-iterate-in-the-array-order-in-php That cleared my understanding of foreach loop in PHP. I prefer your answer, thanks. – Kevin Gagnon Mar 10 '16 at 18:54
Also for some "light" reading: http://stackoverflow.com/questions/10057671/how-does-foreach-actually-work?rq=1 – AbraCadaver Mar 10 '16 at 18:56
Yes ! I actually had the tab openned already. Also, real quick, I am new to stackoverflow, would you have an idea of why my question had a downvote ? There is no question like mine and it was well constructed, I think. Is it because it doesn't serve a "real world job" purpose ? Thanks again. – Kevin Gagnon Mar 10 '16 at 18:59

score 2 · Answer 4 · answered Mar 10 '16 at 17:59

2

I'd try something like this:

<?php

    $myNamedIndexedArray = ['foo' => 'bar', 'go' => 'habs', 'CSGO_bestTeam' => 'fnatic'];

    $myNumberIndexedArray = array_keys($myNamedIndexedArray);
    foreach($myNumberIndexedArray as $key => $value){
        echo $key. " => " . $myNamedIndexedArray[$myNumberIndexedArray[$key]]."<br />";
    }

?>

Adn the output will be:

0 => bar
1 => habs
2 => fnatic

answered Mar 10 '16 at 17:59

Ed de Almeida

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I received both Drudge's answer and yours at the same time and it is the same. That confirms it. Thanks for your time. – Kevin Gagnon Mar 10 '16 at 18:27
It happens. Sometimes we follow the same path, at the same time. The important is that the asnwers helped you. Thanks for the upvote. – Ed de Almeida Mar 10 '16 at 18:56

Get foreach numeric index when keys are named

4 Answers4