php中一维或多维数组去除重复项

Posted 2023-05-06

方案一
$arr = array("0a","1b","2c","3d","4e","5f","6g","0a","2c","4e","6g","6g");
$arr1 = array_flip($arr);
$arr2 = array_flip($arr1);
print_r($arr2);
方案二
$arr = array("0a","1b","2c","3d","4e","5f","6g","0a","2c","4e","6g","6g");
$a = array_count_values($arr);
$b = array_keys($a);
print_r($b);
方案三
$arr = array("0a","1b","2c","3d","4e","5f","6g","0a","2c","4e","6g","6g");
foreach($arr as $k=>$v)
$arr1[$v] = $k;
$arr2 = array_flip($arr1);

print_r($arr2);
方案四
$arr = array("0a","1b","2c","3d","4e","5f","6g","0a","2c","4e","6g","6g");
$arr1 = array_unique($arr);
print_r($arr1);

都是刚刚我实验出来的 都可以封装起来用递归实现多维去掉重复项来自：求助得到的回答 参考技术A array_unique($array);

如果两个值匹配，则从 php 中的多维关联数组中删除重复项

【中文标题】如果两个值匹配，则从 php 中的多维关联数组中删除重复项

【英文标题】：Remove duplicates from multidimensional associative array in php if two values match

【发布时间】：2014-04-14 16:26:53

【问题描述】：

我有一个以下结构的多维数组，我想从中删除重复项。例如，如果两个 ["cities"] 的 ["amount"] 相同，但 ["time"] 相同或不同，那么我认为这是重复的，并希望从数组中删除此节点。

在下面的示例中，我想从数组中完全删除节点 0，因为城市和数量与节点 1 相同。它们都是布里斯托尔（英国布里斯托尔）和 373，尽管时间不同的是 17： 15 点和 17 点 16 分。

如果时间与这种情况不同，那么我会删除以后的时间。

array(8) 
  [0]=>
  array(3) 
    ["time"]=>
    string(5) "17:16"
    ["city"]=>
    string(33) "Bristol (Bristol, United Kingdom)"
    ["amount"]=>
    int(373)
  
  [1]=>
  array(3) 
    ["time"]=>
    string(5) "17:15"
    ["city"]=>
    string(33) "Bristol (Bristol, United Kingdom)"
    ["amount"]=>
    int(373)
  
  [2]=>
  array(3) 
    ["time"]=>
    string(5) "17:16"
    ["city"]=>
    string(37) "Wednesbury (Sandwell, United Kingdom)"
    ["amount"]=>
    int(699)
  
  [3]=>
  array(3) 
    ["time"]=>
    string(5) "17:16"
    ["city"]=>
    string(45) "Wolverhampton (Wolverhampton, United Kingdom)"
    ["amount"]=>
    int(412)
  
  [4]=>
  array(3) 
    ["time"]=>
    string(5) "17:15"
    ["city"]=>
    string(33) "Swansea (Swansea, United Kingdom)"
    ["amount"]=>
    int(249)
  
  [5]=>
  array(3) 
    ["time"]=>
    string(5) "17:16"
    ["city"]=>
    string(39) "Watford (Hertfordshire, United Kingdom)"
    ["amount"]=>
    int(229)
  
  [6]=>
  array(3) 
    ["time"]=>
    string(5) "17:14"
    ["city"]=>
    string(39) "Nottingham (Nottingham, United Kingdom)"
    ["amount"]=>
    int(139)
  
  [7]=>
  array(3) 
    ["time"]=>
    string(5) "17:13"
    ["city"]=>
    string(31) "Dartford (Kent, United Kingdom)"
    ["amount"]=>
    int(103)
  

【参考方案1】：

试试这个：

$result = array();
foreach ($array as $place) 
    if (!array_key_exists($place['time'], $result)) 
        $result[$place['time']] = $place;
    

【参考方案2】：

<?php

$data = array(
    array(
        'time' => '17:16',
        'city' => 'Bristol',
        'amount' => 373,
    ),
    array(
        'time' => '18:16',
        'city' => 'Bristol',
        'amount' => 373,
    ),
    array(
        'time' => '18:16',
        'city' => 'Wednesbury',
        'amount' => 699,
    ),
    array(
        'time' => '19:16',
        'city' => 'Wednesbury',
        'amount' => 699,
    ),
);

$tmp = array();
foreach ($data as $row) 
    $city   = $row['city'];
    $amount = $row['amount'];

    if (!isset($tmp[$city][$amount]) 
        || $tmp[$city][$amount]['time'] < $row['time']) 
        $tmp[$city][$amount] = $row;
    


$data = array();

foreach ($tmp as $cities) 
    foreach ($cities as $city) 
        $data[] = $city;
    


var_dump($data);

【讨论】：

感谢这个工作，我只需要将 $tmp[$city][$amount]['time'] $row['time'] 以便保持较早的时间和较晚的时间。

【参考方案3】：

创建一个二维关联数组，其中一维键控城市，另一维是金额：

$assoc = array();
foreach ($data as $el) 
    $city = $el['city'];
    $amount = $el['amount'];
    if (isset($assoc[$city]) 
        $assoc[$city][$amount] = $el;
     else 
        $assoc[$city] = array($amount => $el);
    


// Now gather up all the elements back into a single array
$result = array();
foreach ($assoc as $cities)
    foreach ($cities as $city) 
        $result[] = $city;