在php中比较数组，而不关心顺序

php arrays comparison set

2022-08-31 00:30:02

我有两个数组，$a和$b在这里，需要检查它们是否包含完全相同的元素（独立于顺序）。我正在考虑使用

if (sizeof($a)==sizeof($b) AND array_diff($a,$b)==array())
{

}

但是我是PHP的新手，所以我想知道：有没有更好的方法？

由于我需要将它们用作集合，也许我根本不应该使用数组，而应该使用其他东西。

答案 1

好吧，我们可以做这样的事情：

if (count(array_diff(array_merge($a, $b), array_intersect($a, $b))) === 0) {
    //they are the same!
}

它之所以有效，是因为array_merge将创建一个大数组，其中包含两者的所有元素和（位于，或两者中的所有元素）。array_intersect将创建一个数组，其中包含两者中的所有元素。因此，如果它们不同，则必须至少有一个元素不会出现在两个数组中...$a$b$a$b$a$b

另请注意，sizeof 不是实际的函数/构造，而是别名。为了清楚起见，我建议使用...count()

答案 2

接受的答案~~是错误的~~。它将在以下情况下失败：https://3v4l.org/U8U5p

$a = ['x' => 1, 'y' => 2]; $b = ['x' => 1, 'y' => 1];

这是一个正确的解决方案：

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;
}

加上相当广泛的单元测试：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 $m\n"; if(!$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：

@ircmaxell答案的广泛单元测试：https://3v4l.org/5ivgm

@Jon轴的广泛单元测试：https://3v4l.org/CrTgQ