PHP uses array_unique to deduplicate two-dimensional arrays

The array_unique function can handle duplicates. It has this function. Let’s take a look at an example of using array_unique in PHP to deduplicate a two-dimensional array.

php 5.2.9 version adds array_unique support for multi-dimensional arrays. When processing multi-dimensional arrays, you need to set the sort_flags parameter

Duplicates of one-dimensional arrays:

Use array_unique The function is enough, the usage example is as follows:

The code is as follows Copy code

<?php
$aa = array("apple", "banana", "pear", "apple", "wail", "watermalon");
$bb = array_unique($aa);
print_r($bb);
?>

The result is as follows:

Array ( [0] => apple [1] => banana [2] => pear [4] => wail [5] => watermalon ) 。

Two-dimensional array deduplication items

The code is as follows Copy code

For example:

$result = array(
0=>array('a'=>1,'b'=>'Hello'),
1=>array('a'=>1,'b'=>'other'),
2=>array('a'=>1,'b'=>'other'),
);

is processed into

$result = array(
0=>array('a'=>1,'b'=>'Hello'),
1=>array('a'=>1,'b'=>'other') 
);

Using method

array_unique($result, SORT_REGULAR);

Duplicates of a two-dimensional array :

We will discuss two-dimensional arrays in two situations. One is because the value of a certain key name cannot be repeated, and duplicates are deleted; the other is because the internal one-dimensional array cannot be exactly the same, and it is deleted. Duplicate items, the following example illustrates:

㈠Because the value of a certain key name cannot be repeated, delete duplicate items

PHP

The code is as follows Copy code

<?php
function assoc_unique($arr, $key) {
$tmp_arr = array();
foreach ($arr as $k => $v) {
if (in_array($v[$key], $tmp_arr)) {//搜索$v[$key]是否在$tmp_arr数组中存在，若存在返回true
unset($arr[$k]);
} else {
$tmp_arr[] = $v[$key];
}
}
sort($arr); //sort函数对数组进行排序
return $arr;
}
$aa = array(
array(&#39;id&#39; => 123, &#39;name&#39; => &#39;张三&#39;),
array(&#39;id&#39; => 123, &#39;name&#39; => &#39;李四&#39;),
array(&#39;id&#39; => 124, &#39;name&#39; => &#39;王五&#39;),
array(&#39;id&#39; => 125, &#39;name&#39; => &#39;赵六&#39;),
array(&#39;id&#39; => 126, &#39;name&#39; => &#39;赵六&#39;)
);
$key = &#39;id&#39;;
assoc_unique(&$aa, $key);
print_r($aa);
?>

The displayed result is:

Array ( [0] => Array ( [id] => 123 [name] => 张三 ) [1] => Array ( [id] => 124 [name] => 王五 ) [2] => Array ( [id] => 125 [name] => 赵六 ) [3] => Array ( [id] => 126 [name] => 赵六 ) )

㈡Because the internal one-dimensional arrays cannot be exactly the same, duplicate items are deleted

The code is as follows Copy code

<?php

function array_unique_fb($array2D) {
foreach ($array2D as $v) {
$v = join(",", $v); //降维,也可以用implode,将一维数组转换为用逗号连接的字符串
$temp[] = $v;
}
$temp = array_unique($temp);//去掉重复的字符串,也就是重复的一维数组
foreach ($temp as $k => $v) {
$temp[$k] = explode(",", $v);//再将拆开的数组重新组装
}
return $temp;
}

$aa = array(
array(&#39;id&#39; => 123, &#39;name&#39; => &#39;张三&#39;),
array(&#39;id&#39; => 123, &#39;name&#39; => &#39;李四&#39;),
array(&#39;id&#39; => 124, &#39;name&#39; => &#39;王五&#39;),
array(&#39;id&#39; => 123, &#39;name&#39; => &#39;李四&#39;),
array(&#39;id&#39; => 126, &#39;name&#39; => &#39;赵六&#39;)
);
$bb = array_unique_fb($aa);
print_r($bb)
?>

Display results:

Array ( [0] => Array ( [0] => 123 [1] => 张三 ) [1] => Array ( [0] => 123 [1] => 李四 ) [2] => Array ( [0] => 124 [1] => 王五 ) [4] => Array ( [0] => 126 [1] => 赵六 ) )