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phparraysarray-filter

Does the array_filter function change the given array in place or return a new array?

Does the array_filter function change the given array in place or return a new array? It's not clear to me from the documentation.

Solution

  • TLDR: Cal is right! array_filter returns a new array, leaving the original unmodified.

    I agree that the documentation for array_filter is unclear. For folks looking for a quick clarification in the future, here is the code and result of the test I wrote to verify.

    code:

    <?php

$testArray = [1,2,3,4,5,6,7,8,9,10];

$filteredArray = array_filter($testArray, function($k) {
  return $k % 2 === 0;
});

print_r($testArray);
print_r($filteredArray);

    result:

    Array
(
    [0] => 1
    [1] => 2
    [2] => 3
    [3] => 4
    [4] => 5
    [5] => 6
    [6] => 7
    [7] => 8
    [8] => 9
    [9] => 10
)
Array
(
    [1] => 2
    [3] => 4
    [5] => 6
    [7] => 8
    [9] => 10
)