Can php arrays be repeated?

The value of the php array can be repeated. The key name of the array is unique and cannot exist repeatedly, but the key value of the array can exist repeatedly. How to handle duplicate values ​​in PHP arrays: 1. Use the "array_unique()" function to remove duplicate values ​​in the array; 2. Use the "array_count_values()" function to count the number of occurrences of all values ​​in the array.

The operating environment of this tutorial: windows10 system, php8.1.3 version, DELL G3 computer.

In PHP, the key name of the array is unique and cannot exist repeatedly, but the key value (value) of the array can exist repeatedly.

$arr=array("A","Cat","Dog","A","Dog","a",3,4);

As you can see, in the above example, the element values ​​"A" and "Dog" have duplicate values.

Processing functions for duplicate values ​​in PHP arrays

For duplicate values, PHP provides a variety of built-in processing functions, two of which are introduced below:

array_unique()

array_count_values()

1. array_unique() function

array_unique() function is used to remove duplicate values ​​in the array. If two or more array values ​​are the same, only the first value is retained and the other values ​​are removed.

Note: The retained array will retain the key type of the first array item.

<?php
header("content-type:text/html;charset=utf-8");
$array = array(1,2,3,3,4,2,3,5,6,4,5,7,8,9,10);
var_dump($array);      
  
$result = array_unique($array);
echo "删除重复元素后的数组";
//var_dump(array_values($filtered_array));
var_dump($result);
?>

2. array_count_values() function

array_count_values() function can count the number of occurrences of all values ​​in the array; if the number is 1, then the element Not repeated.

array_count_values() function will return an associative array, the key name of its element is the value of the original array, and the key value is the number of times the value appears in the original array.

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