PHP user-defined function comparison key name function Array_diff_ukey ()

Instance

Compares the key names of two arrays (using a user-defined function to compare key names) and returns the difference set:

<?phpfunction myfunction ($a, $b) {if ($a = = = $b) {return 0;} return ($a > $b) 1:-1;} $a 1=array ("a" and "Red", "B" and "Green", "c" = "blue"), $a 2=array ("a" and "Blue", "B" and "Black", "e" = "Blue") $result =array_diff_ukey ($a 1, $a 2, "MyFunction");p Rint_r ($result);? >

Definition and usage

The Array_diff_ukey () function is used to compare the key names of two (or more) arrays and return a difference set.

Note: This function uses a user-defined function to compare key names!

The function compares the key names of two (or more) arrays, and returns an array of difference sets that contain all the key names in the array being compared (array1), but not in any other parameter array (array2 or array3, and so on).

Grammar

Array_diff_ukey (array1,array2,array3...,myfunction);

parameters	description
array1	required. The first array to compare with the other array.
array2	required. The array to compare with the first array.
optional. Other arrays compared to the first array
myfunction	required. A string that defines the callable comparison function. If the first parameter is <, =, > The second argument, the corresponding comparison function must return an integer of < =, > 0.

Technical details

return value:	Returns an array of difference sets that contain all the key names in the array being compared (array1), but not in any other parameter array (array2 or array3, and so on).
PHP version:	5.1+

More examples

Example 1

Compares the key names of three arrays (using a user-defined function to compare key names) and returns the difference set:

<?phpfunction myfunction ($a, $b) {if ($a = = = $b) {return 0;} return ($a > $b) 1:-1;} $a 1=array ("a" and "Red", "b" = "green", "c" = "blue"), $a 2=array ("a" and "Black", "B" and "Yellow", "D" and "=" Brown "), $a 3=array (" e "=" purple "," f "=" white "," a "and" gold "); $result =array_diff_ukey ($a 1, $a 2, $a 3," MyFunction ");p Rint_r ($result);? >

1. Function: Use the caller's custom function, according to the key value, returns the difference set of the array;

2. Parameters of the function:

Array $array 1 @params array to be compared

Arrays @params Array $array 2 comparison

Arrays @params Array $array 3 comparison

...

3. Note the point:

1) The custom function returns less than 0, equals 0, or greater than 0, according to the first parameter less than, equal to, or greater than respectively;

4. Example:

<?php$array1 = [' a ' = = 1, ' B ' = = 2, ' c ' = = 3,0 = 4]; $array 2 = [' A ' => ;        1, ' b ' = + 2, ' C ' = 3, ' 0 ' and ' 4 ';p rint_r (Array_diff_ukey ($array 1, $array 2,function ($a, $b) {if ($a = = = $b) {    return 0; } return $a < $b? -1:1;}));