Online PHP editor | output for 0B8hf

@ 2020-07-09T05:25:14Z

<?php

function flatten($array, $prefix = '') {
    $return = [];
    foreach ($array as $key => $value) {
        if (is_array($value)) {
            $return = array_merge($return, flatten($value, $prefix . $key . '_'));
        } else {
            $return[$prefix . $key] = $value;
        }
    }
    return $return;
}


// proof that it's working on the simple cases
var_dump(flatten([
    1, 2, 3 => [4, 5]
]));
var_dump(flatten([
    [1, 2], [3, 4]
])); // use array_values on the result if you don't care about keys

// simple multidimensional array
var_dump(flatten([
    'a' => [
        'b' => 'value',
    ]
]));

// proof that it's not overwriting values like all the other solutions
var_dump(flatten([
    'a' => [
        'b' => 'value',
    ],
    'c' => [
        'b' => 'anothervalue',
    ],
]));

Output for 7.2.0 - 7.2.34, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.4, 8.3.6: array(4) { [0]=> int(1) [1]=> int(2) ["3_0"]=> int(4) ["3_1"]=> int(5) } array(4) { ["0_0"]=> int(1) ["0_1"]=> int(2) ["1_0"]=> int(3) ["1_1"]=> int(4) } array(1) { ["a_b"]=> string(5) "value" } array(2) { ["a_b"]=> string(5) "value" ["c_b"]=> string(12) "anothervalue" }
Output for 8.3.5: Warning: PHP Startup: Unable to load dynamic library 'sodium.so' (tried: /usr/lib/php/8.3.5/modules/sodium.so (libsodium.so.23: cannot open shared object file: No such file or directory), /usr/lib/php/8.3.5/modules/sodium.so.so (/usr/lib/php/8.3.5/modules/sodium.so.so: cannot open shared object file: No such file or directory)) in Unknown on line 0 array(4) { [0]=> int(1) [1]=> int(2) ["3_0"]=> int(4) ["3_1"]=> int(5) } array(4) { ["0_0"]=> int(1) ["0_1"]=> int(2) ["1_0"]=> int(3) ["1_1"]=> int(4) } array(1) { ["a_b"]=> string(5) "value" } array(2) { ["a_b"]=> string(5) "value" ["c_b"]=> string(12) "anothervalue" }

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