How to remove duplicate elements from array in PHP

In PHP, you can use the built-in function "array_unique()" to directly delete duplicate elements, or you can use the "array_flip()" function to indirectly delete duplicate elements.

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array_unique() function

array_unique() function can remove duplicate values ​​​​in the array and return the result array; when the values ​​​​of several array elements are equal, only the first element is retained, and the other elements are delete.

Code example:

<?php
$result1 = array("a" => "green", "red", "b" => "green", "blue", "red");
var_dump($result1);
$result2 = array_unique($result1);
var_dump($result2);
?>

Output:

##array_flip() function

array_flip() is a function that reverses the keys and values ​​of an array. It has a characteristic that if two values ​​​​in the array are the same, then the last key and value will be retained after the reversal. Use We use this feature to indirectly implement array deduplication.

<?php
header("content-type:text/html;charset=utf-8");
$a = array(1, 5, 2, 5, 1, 3, 2, 4, 5);
// 输出原始数组
echo "原始数组 :";
var_dump($a);
// 通过使用翻转键和值移除重复值
$a = array_flip($a);
// 通过再次翻转键和值来恢复数组元素
$a = array_flip($a);
// 重新排序数组键
$a = array_values($a);
// 输出更新后的数组
echo "更新数组 :";
var_dump($a);
?>

Output:

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