PHP: Get key from array? - php

Question

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
)
)

Answer 1

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);
}
?>

Answer 2

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;

Answer 3

$foo = array('a' => 'apple', 'b' => 'ball', 'c' => 'coke');
foreach($foo as $key => $item) {
echo $item.' is begin with ('.$key.')';
}

Answer 4

$array = array(0 => 100, "color" => "red");
print_r(array_keys($array));

Answer 5

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

Answer 6

If you want to be in a foreach loop, then foreach($array as $key => $value) is definitely the recommended approach. Take advantage of simple syntax when a language offers it.

Answer 7

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)

Answer 8

Try this
foreach(array_keys($array) as $nmkey)
{
echo $nmkey;
}

Answer 9

Here is a generic solution that you can add to your Array library. All you need to do is supply the associated value and the target array!
PHP Manual: array_search() (similiar to .indexOf() in other languages)
public function getKey(string $value, array $target)
{
$key = array_search($value, $target);
if ($key === null) {
throw new InvalidArgumentException("Invalid arguments provided. Check inputs. Must be a (1) a string and (2) an array.");
}
if ($key === false) {
throw new DomainException("The search value does not exists in the target array.");
}
return $key;
}