如何獲得PHP中關聯arrays的兩個多維arrays之間的區別？

Question

我的問題是我有兩個 arrays 的大小不一定相同，它們包含始終相同大小的關聯 arrays，例如：

$a = array([0] => array(["ref"]=> string(19) "ygz121byr46dl4795eu", ["place"]=> string(5) "Paris", ["date"]=> string(25) "2012-03-14T16:42:47+01:00", ...), 
           [1] => array(["ref"]=> string(19) "cer123bur45dl4795ef", ["place"]=> string(8) "New-York", ["date"]=> string(25) "2015-06-14T05:05:49+01:00", ...),
           [2] => array(["ref"]=> string(19) "abc123abc12ab1234ab", ["place"]=> string(6) "London", ["date"]=> string(25) "2020-02-12T08:03:39+01:00", ...), 
     ...);

$b = array([0] => array(["ref"]=> string(19) "ygz121byr46dl4795eu", ["place"]=> string(5) "Paris", ["date"]=> string(25) "2012-03-14T16:42:47+01:00", ...), 
           [1] => array(["ref"]=> string(19) "cer123bur45dl4795ef", ["place"]=> string(8) "New-York", ["date"]=> string(25) "2015-06-14T05:05:49+01:00", ...), 
     ...);

我嘗試了幾種方法，但似乎沒有任何效果，或者我只得到沒有值的鍵。 我想在一個數組中得到差異（$a 中的所有元素都不存在 $b），所以這里的結果是：

$result = array( array(["ref"]=> string(19) "abc123abc12ab1234ab", ["place"]=> string(6) "London", ["date"]=> string(25) "2020-02-12T08:03:39+01:00", ...), 
          ...);

“ref”鍵是每個數組的唯一字段，所以我需要在 $result 中所有“ref”鍵不在 $b 中的文檔

編輯：我發現（ https://stackoverflow.com/a/42530586/15742179 ）通過使用array_diff（），array_map（），json_encode（）和decode（）方法來做到這一點。 感謝 Ifnot

// compare all value
$result = array_diff(array_map('json_encode', $a), array_map('json_encode', $b));

// decode the result
$result = array_map('json_decode', $result);

Answer 1

您需要遍歷要過濾的元素集或過濾器集。 這將是一種可能的方法：

<?php
$a = [
  ["ref" => "bee898d8739aa8b2212", "place" => "Berlin"],
  ["ref" => "ygz121byr46dl4795eu", "place" => "Paris"],
  ["ref" => "cer123bur45dl4795ef", "place" => "New-York"],
  ["ref" => "abc123abc12ab1234ab", "place" => "London"]
];

$b = [
  ["ref" => "ygz121byr46dl4795eu", "place" => "Paris"],
  ["ref" => "cer123bur45dl4795ef", "place" => "New-York"],
];

$filter = array_column($b, "ref");
$result = array_combine(array_column($a, "ref"), $a);

array_walk($filter, function($entry) use (&$result) {
  unset($result[$entry]);
});

print_r(array_values($result));

另一種方法是使用 php 的 array_filter() function：

<?php
$a = [
  ["ref" => "bee898d8739aa8b2212", "place" => "Berlin"],
  ["ref" => "ygz121byr46dl4795eu", "place" => "Paris"],
  ["ref" => "cer123bur45dl4795ef", "place" => "New-York"],
  ["ref" => "abc123abc12ab1234ab", "place" => "London"]
];

$b = [
  ["ref" => "ygz121byr46dl4795eu", "place" => "Paris"],
  ["ref" => "cer123bur45dl4795ef", "place" => "New-York"],
];

array_walk($b, function($filter) use (&$a) {
  $a = array_filter($a, function($entry) use ($filter) {
    return $entry["ref"] != $filter["ref"];
  });
});

print_r($a);

output 顯然是：

Array
(
    [0] => Array
        (
            [ref] => bee898d8739aa8b2212
            [place] => Berlin
        )
    [1] => Array
        (
            [ref] => abc123abc12ab1234ab
            [place] => London
        )
)

Answer 2

通過將它們合並在一起來制作一個數組$c ，使用函數array_column和array_unique獲取唯一引用，並通過array_diff_assoc獲取重復項，然后使用array_diff輕松獲取差異引用，然后遍歷數組並僅在$diff數組中獲取它們的引用。

$c = [...$a, ...$b];

$arr = array_column($c, "ref");
$unique = array_unique($arr);
$duplicates = array_diff_assoc($arr, $unique);

$diff = array_diff($unique, $duplicates);
$output = [];
foreach ($c as $d) {
    foreach ($d as $key => $value) {
        if(in_array($d[$key], $diff))
            $output[] = $d;
    }
}
echo "<pre>",print_r($output),"</pre>";

Output ：

Array
(
    [0] => Array
        (
            [ref] => bee898d8739aa8b2212
            [place] => Berlin
        )

    [1] => Array
        (
            [ref] => abc123abc12ab1234ab
            [place] => London
        )

)