如何一次循环遍历两个数组?

2022-01-31 00:00:00 arrays foreach php

我正在尝试将两个数组排列在一起，但结果总是不正确.我将向您展示我的代码、我得到的结果以及我正在寻找的结果.

I am trying to arrange two arrays together and the results keep coming out incorrect. I'll show you my code, the results I'm getting and the results I'm looking for.

我想我只是做错了，但不知道该怎么做.

I guess I'm just doing it wrong but not sure how else to do it.

我的代码:

$data1 = [
    'a: 1',
    'a: 2',
    'a: 3',
    'a: 4',
    'a: 5'
];

$data2 = [
    'b: 1',
    'b: 2',
    'b: 3',
    'b: 4',
    'b: 5'
];


foreach($data1 as $item1)
{
    foreach($data2 as $item2)
    {
        echo $item1 . '<br/>';
        echo $item2 . '<br/>';
        echo '<br/><br/>';
    }
}

结果:(缩短以节省空间)

The Results: (shortened to save space)

a: 1
b: 1

a: 1
b: 2

a: 1
b: 3

a: 1
b: 4

a: 1
b: 5

我正在寻找的结果如下:

The results I'm looking for is the following:

a: 1
b: 1

a: 2
b: 2

a: 3
b: 3

a: 4
b: 4

a: 5
b: 5

推荐答案

问题

问题当然是您的嵌套 foreach 循环.因为对于您的 $data1 数组的每个元素，您都会遍历整个 $data2 数组(所以总共有 $data1 * $data2 次迭代).

Problem

Well the problem is of course your nested foreach loop. Because for each element of your $data1 array you loop through the entire $data2 array (So in total there are $data1 * $data2 iterations).

要解决这个问题，您必须同时遍历两个数组.

To solve this you have to loop through both arrays at once.

您可以使用 array_map() 并将所有要同时循环的数组传递给它.

You can do this with array_map() and pass all arrays to it which you want to loop through at the same time.

array_map(function($v1, $v2){
    echo $v1 . "<br>";
    echo $v2 . "<br><br>";
}, $data1, $data2 /* , Add more arrays if needed manually */);

注意:如果元素的数量不均匀，你不会产生任何错误，它只会打印 NULL (意味着你不会看到任何东西)

Note: If the amount of elements are uneven you won't gen any errors, it will just print NULL (Means you won't see anything)

使用 MultipleIterator 和 附加 ArrayIterator 根据需要.

Use a MultipleIterator and attach as many ArrayIterator as you need.

$it = new MultipleIterator();
$it->attachIterator(new ArrayIterator($data1));
$it->attachIterator(new ArrayIterator($data2));
//Add more arrays if needed 

foreach($it as $a) {
    echo $a[0] . "<br>";
    echo $a[1] . "<br><br>";
}

注意:如果元素的数量不均匀，它将只打印两个数组仍有值的所有值

Note: If the amount of elements are uneven it will just print all values where both arrays still have values

使用带有计数器变量的 for 循环，您可以将其用作两个数组的键.

Use a for loop with a counter variable, which you can use as key for both arrays.

$keysOne = array_keys($data1);
$keysTwo = array_keys($data2);

$min = min(count($data1), count($data2));

for($i = 0; $i < $min; $i++) {
    echo $data1[$keysOne[$i]] . "<br>";
    echo $data2[$keysTwo[$i]] . "<br><br>";
}

注意:使用array_keys() 只是这样，如果数组没有相同的键或关联，这也可以工作.min() 仅用于循环遍历每个数组都有很多元素

或者如果数组只有唯一值，你可以 array_combine() 两个数组，因此 $data1 可以作为键访问，$data2 作为值访问.

Or if the arrays only have unique values, you can array_combine() both arrays, so that $data1 can be accessed as key and $data2 as value.

foreach(array_combine($data1, $data2) as $d1 => $d2) {
    echo $d1 . "<br>";
    echo $d2 . "<br><br>";
}

注意:数组必须有相同数量的元素，否则array_combine()会抛出错误

Note: The arrays must have the same amount of elements, otherwise array_combine() will throw an error

如果您想同时打印超过 2 个数组或只打印未知数量的数组，您可以将 array_map() 方法与 call_user_func_array() 调用.

If you want to print more than 2 arrays at the same time or just an unknown amount of arrays, you can combine the array_map() method with a call_user_func_array() call.

$func = function(...$numbers){
    foreach($numbers as $v)
        echo $v . "<br>";
    echo "<br>";
};
call_user_func_array("array_map", [$func, $data1, $data2]);

注意:由于这有点使用 array_map() 方法，它的行为与不均匀数量的元素相同.此外，由于此方法仅适用于 PHP >=5.6，您只需删除参数并使用 $numbers.func-get-args.php" rel="noreferrer">func_get_args() 在 foreach 循环中，然后它也适用于 PHP >=5.3

Note: Since this kinda uses the array_map() method, it behaves the same with uneven amount of elements. Also since this method only works for PHP >=5.6 you can just remove the arguments and change out $numbers with func_get_args() in the foreach loop and then it also works for PHP >=5.3

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