根据从另一个数组键array_filter [英] array_filter based on keys from another array

问题描述

我有两个数组：

$ ARR1 =阵列（'A'=＆GT; 10，'B'=→20）;

$ ARR2 =阵列（'A'=＆GT; 10，'B'=＆GT; 20，'C'=＆GT; 30）;

我如何使用array_filter下降从 $ ARR2 元素不 $ ARR1 存在吗？就像在我的例子C......

解决方案

有是专门为此做了一个功能：的 array_intersect（）：

  

array_intersect - 计算数组的交集

  $ ARR2 = array_intersect（$ ARR1，$ ARR2）;
 

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如果您想对键进行比较，而不是像 array_intersect（）值，请使用< A HREF =htt​​p://www.php.net/manual/en/function.array-intersect-key.php> array_intersect_key（）：

  

array_intersect_key - 计算使用比较键数组的交集

  $ ARR2 = array_intersect_key（$ ARR1，$ ARR2）;
 

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如果要比较键=＆GT;值对，使用<一个href=\"http://www.php.net/manual/en/function.array-intersect-assoc.php\">array_intersect_assoc():

  

array_intersect_assoc - 计算索引检查数组的交集

  $ ARR2 = array_intersect_assoc（$ ARR1，$ ARR2）;
 

I have two arrays:

$arr1 = array('a' => 10, 'b' => 20);

$arr2 = array('a' => 10, 'b' => 20, 'c' => 30);

How can I use array_filter to drop elements from $arr2 that don't exist in $arr1 ? Like "c" in my example...

解决方案

There is a function specifically made for this purpose: array_intersect():

array_intersect — Computes the intersection of arrays

$arr2 = array_intersect($arr1, $arr2);

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If you want to compare keys, not the values like array_intersect(), use array_intersect_key():

array_intersect_key — Computes the intersection of arrays using keys for comparison

$arr2 = array_intersect_key($arr1, $arr2); 

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If you want to compare key=>value pairs, use array_intersect_assoc():

array_intersect_assoc — Computes the intersection of arrays with additional index check

$arr2 = array_intersect_assoc($arr1, $arr2); 

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