php Array method to remove duplicate values: 1. Use the "array_unique" function to delete duplicates from a one-dimensional array; 2. Delete duplicates from a two-dimensional array through the "assoc_unique" and "array_unique_fb" methods.
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php Array deduplication (one-dimensional array and two-dimensional array Dimensional array)
Removal of duplicate items in the array
Duplicate items in one-dimensional array:
Use the array_unique function. The usage examples are as follows:
<?php
$aa=array("apple","banana","pear","apple","wail","watermalon");
$bb=array_unique($aa);
print_r($bb);
?>The result is as follows: Array ([0] => apple [1] => banana [2] => pear [4] => wail [5] => watermalon ).
Duplicates of two-dimensional arrays:
We will discuss two-dimensional arrays in two situations. One is because the value of a certain key name cannot be repeated, and duplicates are deleted; the other is Because the internal one-dimensional arrays cannot be exactly the same, and duplicates are deleted, the following example illustrates:
Because the value of a certain key name cannot be repeated, delete duplicates
<?php
function assoc_unique($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('id' => 123, 'name' => '张三'),
array('id' => 123, 'name' => '李四'),
array('id' => 124, 'name' => '王五'),
array('id' => 125, 'name' => '赵六'),
array('id' => 126, 'name' => '赵六')
);
$key = 'id';
assoc_unique(&$aa, $key);
print_r($aa);
?>The display 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 ) )
㈡ Because the internal one -dimensional array cannot be exactly the same, delete the duplicate item
<?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('id' => 123, 'name' => '张三'),
array('id' => 123, 'name' => '李四'),
array('id' => 124, 'name' => '王五'),
array('id' => 123, 'name' => '李四'),
array('id' => 126, 'name' => '赵六')
);
$bb=array_unique_fb($aa);
print_r($bb)
?>Display results:
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