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PHP efficiently deduplicates one-dimensional arrays

不言
不言Original
2018-03-29 14:55:522075browse

本文和大家介绍了关于PHP如何高效率对一维数组进行去重的代码,有需要的朋友们可以参考一下。

$input = array("a" => "green", "red", "b" => "green", "blue", "red");
//常见做法:
$result = array_unique($input);


print_r($result);

Array
(
    [a] => green
    [0] => red
    [1] => blue
)
//效率提升:
/*
 * 第一种
 *  思路:键值互换,达到去重目的,但是结果集中键值可能并不是按照数字索引的,可通过array_merge重新生成索引
*/
$result_01 = array_flip($input);
$result_02 = array_flip($result_01);
$result    = array_merge($result_02);

/*
 * 第二种
 * 思路:键值互换,通过array_key直接获取键值,比array_merge()更快
*/
$result_01 = array_flip($input);
$result    = array_key($result_01);

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