PHP uses two user-defined key name comparison functions array_udiff

PHP uses two user-defined key name comparison functions array_udiff_uassoc()

黄舟

Release： 2023-03-17 08:50:01

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Example

Compare the key names and key values of two arrays (use user custom function for comparison), and return the difference set:

<?php
function myfunction_key($a,$b)
{
if ($a===$b)
{
return 0;
}
return ($a>$b)?1:-1;
}

function myfunction_value($a,$b)
{
if ($a===$b)
{
return 0;
}
return ($a>$b)?1:-1;
}

$a1=array("a"=>"red","b"=>"green","c"=>"blue");
$a2=array("a"=>"red","b"=>"green","c"=>"green");

$result=array_udiff_uassoc($a1,$a2,"myfunction_key","myfunction_value");
print_r($result);
?>

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Definition and usage

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

Note: This function uses two user-defined functions for comparison; the first function compares key names, and the second function compares key values!

This function compares the key names and key values of two (or more) arrays, and returns a difference array, which includes everything in the compared array (array1), but not in any other The key name and key value in the parameter array (array2 or array3, etc.).

Syntax

array_udiff_uassoc(array1,array2,array3...,myfunction_key,myfunction_value)

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Parameters	Description
array1	Required. The first array to compare with other arrays.
array2	Required. The array to compare to the first array.
array3,...	Optional. Additional array to compare with the first array.
myfunction_key	Required. The name of the user-defined function used to compare array key names. A string that defines a callable comparison function. If the first argument is <, =, > and the second argument is, the corresponding comparison function must return an integer of <, =, > 0.
myfunction_value	Required. The name of the user-defined function used to compare array key values. A string that defines a callable comparison function. If the first argument is <, =, > and the second argument is, the corresponding comparison function must return an integer of <, =, > 0.

Technical details

Return value:	Returns a difference array, which includes Returns all key names and values that are in the compared array (array1) but not in any other parameter array (array2 or array3, etc.).
PHP version:	5+

##Instance:

<?php

class cr {
    private $priv_member;
    function cr($val) {
        $this->priv_member = $val;
    }
    static function comp_func_cr($a, $b) {
        if ($a->priv_member === $b->priv_member) return 0;
        return ($a->priv_member > $b->priv_member) ? 1 : -1;
    }
    static function comp_func_key($a, $b) {
        if ($a === $b) return 0;
        return ($a > $b) ? 1 : -1;
    }
}
$a = array(
    "0.1" => new cr(9) ,
    "0.5" => new cr(12) ,
    0 => new cr(23) ,
    1 => new cr(4) ,
    2 => new cr(-15) ,
);
$b = array(
    "0.2" => new cr(9) ,
    "0.5" => new cr(22) ,
    0 => new cr(3) ,
    1 => new cr(4) ,
    2 => new cr(-15) ,
);
$result = array_udiff_uassoc($a, $b, array(
    "cr",
    "comp_func_cr"
) , array(
    "cr",
    "comp_func_key"
));
print_r($result);
?>

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Running result:

Array
(
    [0.1] => cr Object
        (
            [priv_member:private] => 9
        )

    [0.5] => cr Object
        (
            [priv_member:private] => 12
        )

    [0] => cr Object
        (
            [priv_member:private] => 23
        )
)

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In the above example, the key-value pair "1" => new cr(4) appears in both arrays at the same time, so it is not in the output of this function. Remember that two

callback functions must be provided.

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