php数组中重复元素的数量

2021-12-21 00:00:00 multidimensional-array php

我们如何找到多维数组中重复元素的数量?

Hi, How can we find the count of duplicate elements in a multidimensional array ?

我有一个这样的数组

Array
(
    [0] => Array
        (
            [lid] => 192
            [lname] => sdsss
        )

    [1] => Array
        (
            [lid] => 202
            [lname] =>  testing
        )

    [2] => Array
        (
            [lid] => 192
            [lname] => sdsss
        )

    [3] => Array
        (
            [lid] => 202
            [lname] =>  testing
        )

)

如何求每个元素的个数?

How to find the count of each elements ?

即，id为192、202等的条目数

i.e, count of entries with id 192,202 etc

推荐答案

你可以采用这个技巧；将数组的每一项(它本身就是一个数组)映射到其各自的 ['lid'] 成员，然后使用 array_count_value() 为您进行计数.

You can adopt this trick; map each item of the array (which is an array itself) to its respective ['lid'] member and then use array_count_value() to do the counting for you.

array_count_values(array_map(function($item) {
    return $item['lid'];
}, $arr);

另外，它是单线的，因此增加了精英黑客的地位.

Plus, it's a one-liner, thus adding to elite hacker status.

从 5.5 开始，您可以将其缩短为:

Since 5.5 you can shorten it to:

array_count_values(array_column($arr, 'lid'));

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