php array_diff() 与多维数组
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array_diff() with multidimensional arrays
提问by Jonathan Chan
Using array_diff(), I can compare and remove similar items, but what if I have the following arrays?
使用array_diff()，我可以比较和删除相似的项目，但是如果我有以下数组怎么办？
Array1
数组1
Array
(
[0] => Array
(
[ITEM] => 1
)
[1] => Array
(
[ITEM] => 2
)
[2] => Array
(
[ITEM] => 3
)
)
Array2
阵列2
Array
(
[0] => Array
(
[ITEM] => 2
)
[1] => Array
(
[ITEM] => 3
)
[2] => Array
(
[ITEM] => 1
)
[3] => Array
(
[ITEM] => 4
)
)
I want to filter out the similar items; result should return 4. How can I rearrange my array so that I can use array_diff()?
我想过滤掉相似的项目；结果应该返回 4。如何重新排列我的数组以便我可以使用array_diff()？
采纳答案by Jason Fingar
I would probably iterate through the original arrays and make them 1-dimensional... something like
我可能会遍历原始数组并使它们成为一维的......就像
foreach($array1 as $aV){
$aTmp1[] = $aV['ITEM'];
}
foreach($array2 as $aV){
$aTmp2[] = $aV['ITEM'];
}
$new_array = array_diff($aTmp1,$aTmp2);
回答by Wiseguy
You can define a custom comparison function using array_udiff().
您可以使用array_udiff().
function udiffCompare($a, $b)
{
return $a['ITEM'] - $b['ITEM'];
}
$arrdiff = array_udiff($arr2, $arr1, 'udiffCompare');
print_r($arrdiff);
Output:
输出：
Array
(
[3] => Array
(
[ITEM] => 4
)
)
This uses and preserves the arrays' existing structure, which I assume you want.
这使用并保留了数组的现有结构，我假设您想要。
回答by Ifnot
Another fun approach with a json_encodetrick (can be usefull if you need to "raw" compare some complex values in the first level array) :
另一个有趣的json_encode技巧（如果您需要“原始”比较第一级数组中的一些复杂值，则可能很有用）：
// Compare all values by a json_encode
$diff = array_diff(array_map('json_encode', $array1), array_map('json_encode', $array2));
// Json decode the result
$diff = array_map('json_decode', $diff);
回答by Mark Amery
A couple of solutions using array_filterthat are less performant than the array_udiffsolutionfor large arrays, but which are a little more straightforward and more flexible:
一些使用array_filter它的解决方案的性能不如大型阵列的array_udiff解决方案，但它们更直接、更灵活：
$array1 = [
['ITEM' => 1],
['ITEM' => 2],
['ITEM' => 3],
];
$array2 = [
['ITEM' => 2],
['ITEM' => 3],
['ITEM' => 1],
['ITEM' => 4],
];
$arrayDiff = array_filter($array2, function ($element) use ($array1) {
return !in_array($element, $array1);
});
// OR
$arrayDiff = array_filter($array2, function ($array2Element) use ($array1) {
foreach ($array1 as $array1Element) {
if ($array1Element['ITEM'] == $array2Element['ITEM']) {
return false;
}
}
return true;
});
As always with array_filter, note that array_filterpreserves the keys of the original array, so if you want $arrayDiffto be zero-indexed, do $arrayDiff = array_values($arrayDiff);after the array_filtercall.
与往常一样array_filter，请注意array_filter保留原始数组的键，因此如果您想要$arrayDiff零索引，请$arrayDiff = array_values($arrayDiff);在array_filter调用后执行。
回答by shiyani suresh
you can use below code to get difference
您可以使用以下代码来获得差异
$a1 = Array(
[0] => Array(
[ITEM] => 1
)
[1] => Array(
[ITEM] => 2
)
[2] => Array(
[ITEM] => 3
)
);
$a2 = Array(
[0] => Array(
[ITEM] => 2
)
[1] => Array(
[ITEM] => 3
)
[2] => Array(
[ITEM] => 1
)
[3] => Array(
[ITEM] => 4
));
array_diff(array_column($a1, 'ITEM'), array_column($a2, 'ITEM'));
回答by AFwcxx
Having the same problem but my multidimensional array has various keys unlike your "ITEM" consistently in every array.
有同样的问题，但我的多维数组在每个数组中都有不同的键，不像你的“ITEM”。
Solved it with: $result = array_diff_assoc($array2, $array1);
解决了它： $result = array_diff_assoc($array2, $array1);
Reference: PHP: array_diff_assoc
回答by Ahmed Abdullah
Compares array1 against one or more other arrays and returns the values in array1 that are not present in any of the other arrays.
将 array1 与一个或多个其他数组进行比较，并返回 array1 中不存在于任何其他数组中的值。
//Enter your code here, enjoy!
$array1 = array("a" => "green", "red", "blue");
$array2 = array("b" => "green", "yellow", "red");
$result = array_diff($array1, $array2);
print_r($result);
