求取关联数组的差集
交并差示例图
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array_diff 函数官方文档截图:https://www.php.net/manual/zh...
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有时在业务逻辑当中我们要获取两个数组的差集,本意是想获取差集,即图中 A-B=a+b 部分,不包含 c 部分.PHP 内置函数中首先想到的是 array_diff() 函数,但 array_diff() 函数传参中第一个 array1 是对比的参照数据,返回的数据是在 array1 中不在其他 array 中的值,显然这并不符合我们的预期.我们可以根据文档测试下 array_diff() 函数返回差集.示例代码
"green", "b" => "red", "c" => "blue", "d" => "pink"];
$array2 = ["a" => "green", "b" => "white", "e" => "yellow", "f" => "pink"];
$result = array_diff($array1, $array2);
print_r($result);
/*
输出内容
Array
(
[b] => red
[c] => blue
)
*///索引数组实例
$array1 = ["green", "red", "blue", "pink"];
$array2 = ["green", "white", "yellow", "pink", "black"];
$result = array_diff($array1, $array2);
print_r($result);
/*
输出内容
Array (
[1] => red
[2] => blue
)
*///文档已经说函数的返回内容,但是可以多次使用 array_diff() 函数对比两个数组来实现我们的目的
//关联数组
$array1 = ["a" => "green", "b" => "red", "c" => "blue", "d" => "pink"];
$array2 = ["a" => "green", "b" => "white", "e" => "yellow", "f" => "pink"];
$result1 = array_diff($array1, $array2);
$result2 = array_diff($array2, $array1);
$result3 = array_merge($result1,$result2);
print_r($result3);
/*
输出内容
Array (
[b] => white
[c] => blue
[e] => yellow
)
*///索引数组
$array1 = ["green", "red", "blue", "pink"];
$array2 = ["green", "white", "yellow", "pink", "black"];
$result1 = array_diff($array1, $array2);
$result2 = array_diff($array2, $array1);
$result3 = array_merge($result1,$result2);
print_r($result3);
/*
输出内容
Array (
[0] => red
[1] => blue
[2] => white
[3] => yellow
[4] => black
)
*/其他方式
从 PHP 官方文档中我们发现有一个 DS 扩展类,位置:"PHP 手册->函数参考->其它基本扩展->Data Structures",从下图中可以看到简介"PHP7高效的数据结构，可以作为 array 的替代",这是 PHP7 中对 array 的一个替代品,通过仔细阅读可知 DS 包含的数据结构能够很好的替代 array 数据结构,提供了更多的数据结构选择.Data Structures :https://www.php.net/manual/zh... 【PHP 求取数组的差集】
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\Ds\Set 和 \Ds\Map 扩展使用实例
"green", "b" => "red", "c" => "blue", "d" => "pink"];
$array2 = ["a" => "green", "b" => "white", "e" => "yellow", "f" => "pink"];
$tpm_1 = new \Ds\Set($array1);
$tpm_2 = new \Ds\Set($array2);
print_r($tpm_1->xor($tpm_2)->toArray());
/*
输出内容
Array (
[0] => red
[1] => blue
[2] => white
[3] => yellow
)
*/
//Ds\Map()
$array1 = ["a" => "green", "b" => "red", "c" => "blue", "d" => "pink"];
$array2 = ["a" => "green", "b" => "white", "e" => "yellow", "f" => "pink"];
$tpm_1 = new \Ds\Map($array1);
$tpm_2 = new \Ds\Map($array2);
print_r($tpm_1->xor($tpm_2)->toArray());
/*
输出内容
Array (
[c] => blue
[d] => pink
[e] => yellow
[f] => pink
)
*/
//索引数组
//Ds\Set()
$array1 = ["green", "red", "blue", "pink"];
$array2 = ["green", "white", "yellow", "pink", "black"];
$tpm_1 = new \Ds\Set($array1);
$tpm_2 = new \Ds\Set($array2);
print_r($tpm_1->xor($tpm_2)->toArray());
/*
输出内容
Array (
[0] => red
[1] => blue
[2] => white
[3] => yellow
[4] => black
)
*/
//Ds\Map()
$array1 = ["green", "red", "blue", "pink"];
$array2 = ["green", "white", "yellow", "pink", "black"];
$tpm_1 = new \Ds\Map($array1);
$tpm_2 = new \Ds\Map($array2);
print_r($tpm_1->xor($tpm_2)->toArray());
/*
输出内容
Array (
[4] => black
)
*/
