PHP array_unique implements two-dimensional array deduplication

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array_unique The function can be used to handle duplicates. It has this function. Let’s take a look at the use of array_unique in PHP Two-dimensional array deduplication processing example.

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

Duplication of one-dimensional arrays Item:

Just use the array_unique function. The usage example is as follows:

The code is as follows

<?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 Item

The code is as follows

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')
);

Usage method

array_unique($result, SORT_REGULAR);

Duplicates of two-dimensional arrays:

For two-dimensional arrays, we will discuss it 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 The arrays cannot be exactly the same, and duplicates are deleted. The following is an example:

Because the value of a certain key name cannot be duplicated, duplicates are deleted

The PHP code is as follows

<?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 ) )

Because the internal one-dimensional arrays cannot be exactly the same, and duplicates are deleted

The code is as follows

<?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)
?>

The displayed result is:

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 ) )

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