删除数组特定值相同/唯一的二维数组元素（第一个匹配除外）答案

【问题标题】：Remove two dimentional array elements(except first match) which array specific value are same/unique删除数组特定值相同/唯一的二维数组元素（第一个匹配除外）
【发布时间】：2021-03-25 06:31:19
【问题描述】：

例如我下面有一个二维数组，

$a = array(
    "one" => array (
        "id" => 111,
        "name" => "Jhon"
    ),
    "two" => array(
        "id" => 222,
        "name" => "Adam"
    ),
    "three" => array(
        "id" => 111,
        "name" => "Mark"
    ),
    "four" => array(
        "id" => 125,
        "name" => "Jhon"
    ),
    "five" => array(
        "id" => 111,
        "name" => "Jhon"
    ),
    "six" => array(
        "id" => 222,
        "name" => "Rock"
    ),
);

我想删除二维数组值相同/唯一的数组（第一个匹配除外）。例如，我想删除所有 id 键值相同的数组（第一个匹配除外）。如，数组id键值111（数组计数为3）和222（数组计数为2）。因此，在删除唯一键 id 后，结果数组应如下所示，

$a = array(
    "one" => array (
        "id" => 111,
        "name" => "Jhon"
    ),
    "two" => array(
        "id" => 222,
        "name" => "Adam"
    ),
    "four" => array(
        "id" => 125,
        "name" => "Jhon"
    ),
);

【问题讨论】：

标签： php arrays unique

【解决方案1】：

您需要保留一个带有添加键的数组。您可以使用array_filter() 删除不必要的行。

代码：(demo)

$array = [
    "one"   => ["id" => 111, "name" => "Jhon"],
    "two"   => ["id" => 222, "name" => "Adam"],
    "three" => ["id" => 111, "name" => "Mark"],
    "four"  => ["id" => 125, "name" => "Jhon"],
    "five"  => ["id" => 111, "name" => "Jhon"],
    "six"   => ["id" => 222, "name" => "Rock"],
];

// store added IDs
$added = [];

// filter array (need to pass $added as reference to be updated)
$output = array_filter($array, function($item) use (&$added) 
{
    // shortcut for readability
    $id = $item['id'];  
    // Check if id already exists
    if (isset($added[$id])) { return false; } 
    // add to reference
    $added[$id] = true; 
    // add to final array
    return true; 
});

unset($added); // no longer needed.

var_dump($output);

输出：

array(3) {
  ["one"]=>
  array(2) {
    ["id"]=>
    int(111)
    ["name"]=>
    string(4) "Jhon"
  }
  ["two"]=>
  array(2) {
    ["id"]=>
    int(222)
    ["name"]=>
    string(4) "Adam"
  }
  ["four"]=>
  array(2) {
    ["id"]=>
    int(125)
    ["name"]=>
    string(4) "Jhon"
  }
}

【讨论】：

【解决方案2】：

使用此代码完成您的任务

    <?php
$a = array(
    "one" => array (
        "id" => 111,
        "name" => "Jhon"
    ),
    "two" => array(
        "id" => 222,
        "name" => "Adam"
    ),
    "three" => array(
        "id" => 111,
        "name" => "Mark"
    ),
    "four" => array(
        "id" => 125,
        "name" => "Jhon"
    ),
    "five" => array(
        "id" => 111,
        "name" => "Jhon"
    ),
    "six" => array(
        "id" => 222,
        "name" => "Rock"
    ),
);
$unique = [];
$final_array = [];
foreach ($a as  $value) {
    if(in_array($value['id'],$unique)){
        continue;
    }
    else {
        $unique[] = $value['id'];
        $final_array[] = $value;
    }
} 
echo "<pre>";
print_r($final_array);
?>

这里我使用了一个唯一的命名数组，我在其中放置唯一键并循环遍历数组，如果 id 存在于唯一的然后它跳过，否则我将它添加到最终数组中。希望这能解决您的问题。

【讨论】：

final_array 中缺少键（one、two 和 four）。