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up vote 19 down vote favorite
9

I am sure that this is super easy and built-in function in PHP, but I have yet not seen it.

Here's what I am doing for the moment:

foreach($array as $key => $value) {
    echo $key; // Would output "subkey" in the example array
    print_r($value);
}

Could I do something like the following instead and thereby save myself from writing "$key => $value" in every foreach loop? (psuedocode)

foreach($array as $subarray) {
    echo arrayKey($subarray); // Will output the same as "echo $key" in the former example ("subkey"
    print_r($value);
}

Thanks!

The array:

Array
(
    [subKey] => Array
        (
            [value] => myvalue
        )

)
share|improve this question
7  
Whats wrong with foreach($array as $key => $value)? Or, asked the other way around, what's the point using foreach($array as $value) when you actually need $key somewhere down the road? –  Tomalak Jul 23 '10 at 12:10
2  
I just thought it could be a good idea to get the key in a quick way –  Industrial Jul 23 '10 at 12:12
1  
But you do get it in a quick way with foreach($array as $key => $value)... :-) Or is the situation not that you are in a foreach loop? –  Tomalak Jul 23 '10 at 12:14
    
I am in a foreach loop for sure, but what i've thought about was to not change the foreach statement, but just printing out the key. –  Industrial Jul 23 '10 at 12:21
2  
Every function call you could make would be less efficient than simply changing to the appropriate foreach loop construct. –  Tomalak Jul 23 '10 at 13:48

7 Answers 7

up vote 34 down vote accepted

You can use key():

<?php
$array = array(
    "one" => 1,
    "two" => 2,
    "three" => 3,
    "four" => 4
);

while($element = current($array)) {
    echo key($array)."\n";
    next($array);
}
?>
share|improve this answer
4  
Hi! But key doesnt work in a foreach, right? –  Industrial Jul 23 '10 at 12:49
1  
Yes, that is correct. You need to use while-loop for key(). –  vtorhonen Jul 23 '10 at 12:59
2  
I want to add that you can use key() ANYWHERE but for this problem it make sense to use it in a while-loop. You can use key() in the instance of only wanting the first/current array element's key. –  J.Romero Nov 21 '12 at 19:50
2  
@Industrial foreach uses the key... if you want to use foreach, do this: foreach($array as $key => $value) { ... } –  Greg Oct 16 '13 at 15:27
up vote 1 down vote

Dogbert's solution was my preferred answer to this, thanks.

        foreach ($array as $key => $value) {
            echo "$key: $value <br />";
        }
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up vote 0 down vote

Another way to use key($array) in a foreach loop is by using next($array) at the end of the loop, just make sure each iteration calls the next() function (in case you have complex branching inside the loop)

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up vote 7 down vote 
$foo = array('a' => 'apple', 'b' => 'ball', 'c' => 'coke');

foreach($foo as $key => $item) {
  echo $item.' is begin with ('.$key.')';
}
share|improve this answer
up vote 4 down vote

If it IS a foreach loop as you have described in the question, using $key => $value is fast and efficient.

share|improve this answer
up vote 10 down vote 

$array = array(0 => 100, "color" => "red");
print_r(array_keys($array));
share|improve this answer
    
what's d difference? –  gumuruh Apr 18 '12 at 9:17
up vote 26 down vote

Use the array_search function.

Example from php.net

$array = array(0 => 'blue', 1 => 'red', 2 => 'green', 3 => 'red');

$key = array_search('green', $array); // $key = 2;
$key = array_search('red', $array);   // $key = 1;
share|improve this answer
    
Hi, updated my original post with an array example. Thanks! –  Industrial Jul 23 '10 at 12:03

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