I have two arrays, $a and $b here, and need to check if they contain exactly the same elements (independently of the order). I am thinking of using
if (sizeof($a)==sizeof($b) AND array_diff($a,$b)==array()) { }
But I am new to PHP, so I wonder: Is there a better way?
Since I need to use them as sets, maybe I should not use arrays at all but something else.
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Answer
The accepted answer is was wrong. It will would fail on: https://3v4l.org/U8U5p
$a = ['x' => 1, 'y' => 2]; $b = ['x' => 1, 'y' => 1];
Here is a correct solution:
function consistsOfTheSameValues(array $a, array $b) { // check size of both arrays if (count($a) !== count($b)) { return false; } foreach ($b as $key => $bValue) { // check that expected value exists in the array if (!in_array($bValue, $a, true)) { return false; } // check that expected value occurs the same amount of times in both arrays if (count(array_keys($a, $bValue, true)) !== count(array_keys($b, $bValue, true))) { return false; } } return true; }
Plus quite extensive unit tests: https://3v4l.org/m6lHv
<?php // A unit testing framework in a tweet. https://gist.github.com/mathiasverraes/9046427 function it($m,$p){echo ($p?'✔︎':'✘')." It $mn"; if(!$p){$GLOBALS['f']=1;}}function done(){if(@$GLOBALS['f'])die(1);} function consistsOfTheSameValues(array $a, array $b) { // check size of both arrays if (count($a) !== count($b)) { return false; } foreach ($b as $key => $bValue) { // check that expected value exists in the array if (!in_array($bValue, $a, true)) { return false; } // check that expected value occurs the same amount of times in both arrays if (count(array_keys($a, $bValue, true)) !== count(array_keys($b, $bValue, true))) { return false; } } return true; } it('consist of the same values', consistsOfTheSameValues([1], [1]) === true ); it('consist of the same values', consistsOfTheSameValues([1, 1], [1, 1]) === true ); it('consist of the same values', consistsOfTheSameValues(['1', 1], ['1', 1]) === true ); it('consist of the same values', consistsOfTheSameValues(['1', 1], [1, '1']) === true ); it('consist of the same values', consistsOfTheSameValues([1, '1'], ['1', 1]) === true ); it('consist of the same values', consistsOfTheSameValues([1, '1'], [1, '1']) === true ); it('consist of the same values', consistsOfTheSameValues(['x' => 1], ['x' => 1]) === true ); it('consist of the same values', consistsOfTheSameValues(['x' => 1], ['y' => 1]) === true ); it('consist of the same values', consistsOfTheSameValues(['y' => 1], ['x' => 1]) === true ); it('consist of the same values', consistsOfTheSameValues(['x' => 1, 'y' => 1], ['x' => 1, 'y' => 1]) === true ); it('consist of the same values', consistsOfTheSameValues(['y' => 1, 'x' => 1], ['x' => 1, 'y' => 1]) === true ); it('consist of the same values', consistsOfTheSameValues(['x' => 1, 'y' => 1], ['y' => 1, 'x' => 1]) === true ); it('consist of the same values', consistsOfTheSameValues(['y' => 1, 'x' => 1], ['y' => 1, 'x' => 1]) === true ); it('consist of the same values', consistsOfTheSameValues(['x' => 2, 'y' => 1], ['x' => 1, 'y' => 2]) === true ); it('does not consist of the same values', consistsOfTheSameValues([1], [2]) === false ); it('does not consist of the same values', consistsOfTheSameValues(['1'], [1]) === false ); it('does not consist of the same values', consistsOfTheSameValues([1], ['1']) === false ); it('does not consist of the same values', consistsOfTheSameValues([1], [1, 1]) === false ); it('does not consist of the same values', consistsOfTheSameValues([1, 1], [1]) === false ); it('does not consist of the same values', consistsOfTheSameValues(['1', 1], [1, 1]) === false ); it('does not consist of the same values', consistsOfTheSameValues([1, '1'], [1, 1]) === false ); it('does not consist of the same values', consistsOfTheSameValues([1, 1], ['1', 1]) === false ); it('does not consist of the same values', consistsOfTheSameValues([1, 1], [1, '1']) === false ); it('does not consist of the same values', consistsOfTheSameValues(['1', '1'], [1, 1]) === false ); it('does not consist of the same values', consistsOfTheSameValues(['1', '1'], ['1', 1]) === false ); it('does not consist of the same values', consistsOfTheSameValues(['1', '1'], [1, '1']) === false ); it('does not consist of the same values', consistsOfTheSameValues([1, 1], ['1', '1']) === false ); it('does not consist of the same values', consistsOfTheSameValues(['1', 1], ['1', '1']) === false ); it('does not consist of the same values', consistsOfTheSameValues([1, '1'], ['1', '1']) === false ); it('does not consist of the same values', consistsOfTheSameValues(['x' => 1], ['x' => 2]) === false ); it('does not consist of the same values', consistsOfTheSameValues(['x' => 1, 'y' => 1], ['x' => 1, 'y' => 2]) === false ); it('does not consist of the same values', consistsOfTheSameValues(['x' => 1, 'y' => 1], ['x' => 2, 'y' => 1]) === false ); it('does not consist of the same values', consistsOfTheSameValues(['x' => 2, 'y' => 1], ['x' => 1, 'y' => 1]) === false );
@update:
Extensive unit test of @ircmaxell answer: https://3v4l.org/5ivgm
Extensive unit test of @Jon anwser: https://3v4l.org/CrTgQ