Question 40554 in PHP Question posted in
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Get key (not index) from qualifying row in an associative array of associative arrays – PHP

Here my array:

$array = [
    'key1' => [
        'first' => 'azerty',
        'second' => 'qwerty'
    ],
    'key2' => [
        'first' => 'hello',
        'second' => 'world'
    ]
];

With the value ‘qwerty’ I would like to retrieve the ‘key1’.

I looking for something like that:

$theKeyIWant = array_search('qwerty', array_column($array, 'second'));

But I get ‘0’, instead of ‘key1’ (and I know that’s how it works)

Anyone know how to adapt this code or know another code to get the key value?

Tags:

4

Answers


  1. 0

    To solve this is to loop through the outer array and use array_search() to search for the value within each inner array.

    $value = 'qwerty';
$theKeyIWant = null;

foreach ($array as $key => $innerArray) {
  if (array_search($value, $innerArray) !== false) {
    $theKeyIWant = $key;
    break;
  }
}

echo $theKeyIWant; // Output: key1
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  2. 0

    array_keys returns an array of an array’s keys.

    <?php

$array = [
'key1' => [
    'first' => 'azerty',
    'second' => 'qwerty'
],
'key2' => [
    'first' => 'hello',
    'second' => 'world'
]
];
$theKeyIWant = array_search('qwerty', array_column($array, 'second'));
echo array_keys($array)[$theKeyIWant];
?>

    3V4l

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  3. 0

    Slight modification to your code to combine the keys and column values:

    $theKeyIWant = array_search('qwerty', array_combine(array_keys($array), array_column($array, 'second')));
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  4. 0

    The problem with seeking "something sexier" for this task is that if "sexier" means a "functional iterator", then that comes a cost of not being able to "return early" (doing unnecessary cycles).

    If you want a single-line function to call, you can build your own and put it in a helpers file somewhere in your project. My strong advice is to abandon "sexy" for this task and use a breakable foreach loop.

    Code: (Demo)

    function getRowKey($array, $column, $value) {
    foreach ($array as $key => $row) {
        if ($row[$column] === $value) {
            return $key;
        }
    }
    return null;
}

var_export(getRowKey($array, 'second', 'qwerty'));

    If you are going to perform repeated searches on the same array and the second column is guaranteed to contain unique values, then you can convert the array into a lookup array without losing any data. (Demo)

    function restructure($array, $columnToKey) {
    $result = [];
    foreach ($array as $key => $row) {
        $result[$row[$columnToKey]] = $row + ['oldKey' => $key];
    }
    return $result;
}

var_export(restructure($array, 'second')['qwerty']);
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