How to delete array with duplicate key values ​​in php

In the process of using PHP for web development, we often encounter situations where we need to operate on arrays. When duplicate key values ​​appear in the array, if they are not processed, it will cause the program to run abnormally. This article will introduce how to use PHP to delete duplicate key values ​​​​in an array.

1. Use the array_unique() function

In PHP, you can use the array_unique() function to remove duplicate elements from an array. This function will return a new array. It does not contain any duplicate values. Using this function is very simple. You only need to pass in the array that needs to be processed as a parameter of the function. The specific implementation is as follows:

$fruits = array("apple", "banana", "orange", "apple");

$unique_fruits = array_unique($fruits);

print_r($unique_fruits);

The above code will output:

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

In this code , we first define an array $fruits containing duplicate values, then use the array_unique() function to remove the duplicate values, and assign the result to the $unique_fruits array. Finally, use the print_r() function to output the $unique_fruits array. You can see that the duplicate value "apple" has been deleted.

2. Using loop traversal

In addition to using the array_unique() function, we can also delete duplicate key values ​​​​in an array through loop traversal. The principle is that we use a new array to store the elements that have been traversed. Each time an element in the array is traversed, it is judged whether the element has already appeared in the new array. If not, the element is stored in the new array. array. The code is as follows:

$fruits = array("apple", "banana", "orange", "apple");

$unique_fruits = array();

foreach ($fruits as $fruit) {
    if (!in_array($fruit, $unique_fruits)) {
        $unique_fruits[] = $fruit;
    }
}

print_r($unique_fruits);

The above code will also output:

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

In this code, we define a new array $unique_fruits, and then use a foreach loop to traverse the elements in the $fruits array. During each traversal, use the in_array() function to determine whether the element appears in the $unique_fruits array. If it does not appear, add the element to the end of the $unique_fruits array. Finally, use the print_r() function to output the contents of the $unique_fruits array.

Summary

Whether you use the array_unique() function or loop traversal, deleting duplicate key values ​​​​in a PHP array is very simple. Which method to use depends on the specific situation and personal preference. In actual development, we need to choose the most appropriate method to process arrays based on the actual situation to ensure the normal operation of the program.

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