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PHP array_diff () function

PHP Array Reference Complete PHP Array Reference

Examples

Comparison of two arrays of keys and returns the difference set:

<?php
$a1=array("a"=>"red","b"=>"green","c"=>"blue","d"=>"yellow");
$a2=array("e"=>"red","f"=>"green","g"=>"blue");

$result=array_diff($a1,$a2);
print_r($result);
?>

Running instance »

Definition and Usage

array_diff () function is used to compare two (or more) of the array keys, and returns the set difference.

This function compares two (or more) key array, and returns a difference of arrays, the array includes all the compared array (array1), but not in any other parameter array (array2 or array3 etc. ) of the key.


grammar

array_diff( array1,array2,array3... );

参数 描述
array1 必需。与其他数组进行比较的第一个数组。
array2 必需。与第一个数组进行比较的数组。
array3,... 可选。与第一个数组进行比较的其他数组。

technical details

return value: Returns a difference of arrays, the array includes all the compared array (array1), but not in any other parameter array (array2 or array3 etc.) in the key.
PHP version: 4.0.1+


More examples

Example 1

Comparison of three arrays of keys, and returns the difference between sets:

<?php
$a1=array("a"=>"red","b"=>"green","c"=>"blue","d"=>"yellow");
$a2=array("e"=>"red","f"=>"black","g"=>"purple");
$a3=array("a"=>"red","b"=>"black","h"=>"yellow");

$result=array_diff($a1,$a2,$a3);
print_r($result);
?>

Running instance »


PHP Array Reference Complete PHP Array Reference