如何从多维数组中删除重复值? [英] How to remove duplicate values from a multidimensional array?

问题描述

我有来自两个单独的 mysql 查询的数组数据.数组数据如下所示:

I have array data from two separate mysql queries. Array data looks like below:

0
:
{user_id: 82, ac_type: 1,…}
1
:
{user_id: 80, ac_type: 5,…}
2
:
{user_id: 76, ac_type: 1,…}
3
:
{user_id: 82, ac_type: 1,…}
4
:
{user_id: 80, ac_type: 5,…}

我想删除重复的数组项.

I want to remove the duplicate array items.

所以，我的输出会是这样的:

So, my output will be like this:

0
:
{user_id: 82, ac_type: 1,…}
1
:
{user_id: 80, ac_type: 5,…}
2
:
{user_id: 76, ac_type: 1,…}

我想通过 user_id 检查重复.

I want to check duplicate by user_id.

我尝试了以下解决方案，但都没有按预期工作.

I have tried the following solutions, but neither are not working as desired.

$input = array_unique($res, SORT_REGULAR);

$input = array_map("unserialize", array_unique(array_map("serialize", $res)));

下面我也试过了.

$results = array();

foreach ($res as $k => $v) {
        $results[implode($v)] = $v;
}

$results = array_values($results);
print_r($results);

但仍然存在重复数据.

推荐答案

此任务不需要任何自定义函数调用.只需使用 array_column() 为每个子数组分配新的临时键，然后重新索引子数组并打印到屏幕上.*这确实会用较晚的事件覆盖较早的事件.

You don't need any custom function calls for this task. Just use array_column() to assign new temporary keys to each subarray, then reindex the subarrays and print to screen. *this does overwrite earlier occurrences with later ones.

代码:(演示)

$array=[
    ['user_id'=>82,'ac_type'=>1],
    ['user_id'=>80,'ac_type'=>5],
    ['user_id'=>76,'ac_type'=>1],
    ['user_id'=>82,'ac_type'=>2],
    ['user_id'=>80,'ac_type'=>6]
];
var_export(array_values(array_column($array,NULL,'user_id')));

输出:

array (
  0 => 
  array (
    'user_id' => 82,
    'ac_type' => 2,
  ),
  1 => 
  array (
    'user_id' => 80,
    'ac_type' => 6,
  ),
  2 => 
  array (
    'user_id' => 76,
    'ac_type' => 1,
  ),
)

<小时>

如果您想保留第一次出现并忽略所有后续重复项，则可以这样做:

---

If you want to keep the first occurrences and ignore all subsequent duplicates, this will do:

代码:(Demo)(* 保留第一次出现)

Code: (Demo) (* this keeps the first occurrences)

$array=[
    ['user_id'=>82,'ac_type'=>1],
    ['user_id'=>80,'ac_type'=>5],
    ['user_id'=>76,'ac_type'=>1],
    ['user_id'=>82,'ac_type'=>2],
    ['user_id'=>80,'ac_type'=>6]
];

foreach($array as $a){
    if(!isset($result[$a['user_id']])){
        $result[$a['user_id']]=$a;      // only store first occurence of user_id
    }
}
var_export(array_values($result));  // re-index

输出:

array (
  0 => 
  array (
    'user_id' => 82,
    'ac_type' => 1,
  ),
  1 => 
  array (
    'user_id' => 80,
    'ac_type' => 5,
  ),
  2 => 
  array (
    'user_id' => 76,
    'ac_type' => 1,
  ),
)

<小时>

如果您不介意丢失子数组的顺序，可以使用 array_reverse() 和 array_column() 来使用临时键保留第一次出现，然后使用 array_values() 重新索引:

---

If you don't mind losing the order of your subarrays, you can use array_reverse() with array_column() to retain the first occurrences using temporary keys, then use array_values() to re-index:

var_export(array_values(array_column(array_reverse($array),NULL,'user_id')));
/*
array (
  0 => 
  array (
    'user_id' => 76,
    'ac_type' => 1,
  ),
  1 => 
  array (
    'user_id' => 82,
    'ac_type' => 1,
  ),
  2 => 
  array (
    'user_id' => 80,
    'ac_type' => 5,
  ),
)
*/

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