How to define a unique array in php

To define a unique array in PHP, you can use the array_unique() function. This function can remove duplicate key values ​​​​in the array and return a new array. The following is the specific code implementation:

// 定义一个包含重复键值的数组
$arr = array(1, 2, 3, 4, 2, 3, 5);

// 使用 array_unique() 函数去除重复键值
$new_arr = array_unique($arr);

// 输出新数组
print_r($new_arr);

Run the above code, you will get the following output:

Array
(
    [0] => 1
    [1] => 2
    [2] => 3
    [3] => 4
    [6] => 5
)

As you can see, the duplicate key values ​​2 and ## in the array #3 is removed and a new non-duplicate array is generated.

In actual development, if you need to define a non-duplicate array, it is best to remove duplicate key values ​​when the array is initialized to avoid problems in subsequent operations. The following is an example:

// 定义一个含有重复键值的数组
$arr = array('apple', 'orange', 'banana', 'apple', 'pear', 'banana');

// 使用 array_unique() 函数去除重复键值，生成一个不重复的数组
$new_arr = array_unique($arr);

// 将新数组赋值给旧数组，完成去重
$arr = $new_arr;

// 输出不重复的数组
print_r($arr);

Run the above code, you will get the following output:

Array
(
    [0] => apple
    [1] => orange
    [2] => banana
    [4] => pear
)

As you can see, the duplicate key values ​​​​

apple and banana in the array was removed, a new non-duplicate array was generated, and the original array was reassigned into a non-duplicate array.

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