Tác dụng của hàm array_udiff_uassoc()
The array_udiff_uassoc() function compares the keys and values of two or more arrays and returns the differences using the user-defined key and value comparison functions.
The following table summarizes the technical details of this function.
| Return Value: | Returns an array containing all the elements from array1 that are not present in any of the other arrays. |
|---|---|
| Version: | PHP 5+ |
Syntax
The basic syntax of the array_udiff_uassoc() function is given with:
The following example shows the array_udiff_uassoc() function in action.
Example
Run this code »<?php
// Define comparison functions
function compareKey($a, $b){
if($a == $b){
return 0;
}
return ($a < $b) ? -1 : 1;
}
function compareValue($a, $b){
// Converting value to lowercase
$a = strtolower($a);
$b = strtolower($b);
if($a == $b){
return 0;
}
return ($a < $b) ? -1 : 1;
}
// Sample arrays
$array1 = array("a"=>"apple", "b"=>"ball", "c"=>"cat", "dog");
$array2 = array("a"=>"APPLE", "B"=>"ball", "c"=>"Cat");
// Computing the difference
$result = array_udiff_uassoc($array1, $array2, "compareValue", "compareKey");
print_r($result);
?>Note: The comparison function must return an integer equal to zero if both arguments are equal, an integer less than zero if the first argument is less than the second, and an integer greater than zero if the first argument is greater than the second argument.
Parameters
The array_udiff_uassoc() function accepts the following parameters.
| Parameter | Description |
|---|---|
| array1 | Required. Specifies the array to compare from. |
| array2 | Required. Specifies an array to compare against. |
| ... | Optional. Specifies more arrays to compare against. |
| value_compare_function | Required. Specifies a callback function to use for value comparison. |
| key_compare_function | Required. Specifies a callback function to use for key comparison. |
More Examples
Here're some more examples showing how array_udiff_uassoc() function actually works:
The following example shows how to compare the keys and values of the three arrays and get the differences using the PHP's built-in strcasecmp() function as comparison function.
Example
Run this code »<?php
// Sample arrays
$array1 = array("a"=>"apple", "b"=>"ball", "c"=>"cat", "d"=>"dog");
$array2 = array("a"=>"APPLE", "B"=>"ball", "c"=>"camel");
$array3 = array("d"=>"DOG", "e"=>"elephant");
// Computing the difference
$result = array_udiff_uassoc($array1, $array2, $array3, "strcasecmp", "strcasecmp");
print_r($result);
?>