关于array_diff_uassoc的疑问
程序员文章站
2022-04-30 13:44:58
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源码:
$b)? 1:-1;
}
$array1 = array("a" => "green", "b" => "brown", "c" => "blue", "red");
$array2 = array("a" => "green", "yellow", "red");
$result = array_diff_uassoc($array1, $array2, "key_compare_func");
print_r($result);
结果:
string(1) "b"
string(1) "a"
=====1
string(1) "b"
string(1) "c"
=====2
int(0)
string(1) "b"
=====3
string(1) "a"
int(0)
=====4
int(0)
string(1) "a"
=====5
int(1)
int(0)
=====6
string(1) "a"
int(0)
=====7
string(1) "a"
string(1) "a"
=====8
int(0)
string(1) "a"
=====8
int(0)
int(0)
=====9
string(1) "b"
string(1) "a"
=====9
string(1) "b"
int(0)
=====10
string(1) "b"
int(1)
=====11
string(1) "c"
string(1) "a"
=====12
string(1) "c"
int(0)
=====13
string(1) "c"
int(1)
=====14
Array
(
[b] => brown
[c] => blue
[0] => red
)
请问:
对于这个函数,他的比较原理是什么?为什么要进行14次比较?
回复内容:
源码:
$b)? 1:-1;
}
$array1 = array("a" => "green", "b" => "brown", "c" => "blue", "red");
$array2 = array("a" => "green", "yellow", "red");
$result = array_diff_uassoc($array1, $array2, "key_compare_func");
print_r($result);
结果:
string(1) "b"
string(1) "a"
=====1
string(1) "b"
string(1) "c"
=====2
int(0)
string(1) "b"
=====3
string(1) "a"
int(0)
=====4
int(0)
string(1) "a"
=====5
int(1)
int(0)
=====6
string(1) "a"
int(0)
=====7
string(1) "a"
string(1) "a"
=====8
int(0)
string(1) "a"
=====8
int(0)
int(0)
=====9
string(1) "b"
string(1) "a"
=====9
string(1) "b"
int(0)
=====10
string(1) "b"
int(1)
=====11
string(1) "c"
string(1) "a"
=====12
string(1) "c"
int(0)
=====13
string(1) "c"
int(1)
=====14
Array
(
[b] => brown
[c] => blue
[0] => red
)
请问:
对于这个函数,他的比较原理是什么?为什么要进行14次比较?
查阅了一下源码,在比较之前,PHP还进行了一次排序操作,排序时也会采用这个回调函数,这也就是你会看到结果中会有b
和c
这两个出现在同一个数组中的键进行比较的记录。