How to delete duplicate elements in php array

PHP is a commonly used programming language, and its array function is very powerful. When using PHP arrays, we often encounter situations where we need to delete duplicate elements in the array. This article will introduce two methods to remove duplicate elements in PHP arrays.

Method 1: Use the array_unique function

The array_unique function is a function in PHP specifically used to remove duplicate elements from an array. Its use is very simple, just pass the deduplicated array as a parameter to the function:

<?php
$originalArray = array(1, 2, 3, 2, 4, 5, 3, 6);
$uniqueArray = array_unique($originalArray);
print_r($uniqueArray);
?>

In the above code, we first create an original array $originalArray, which contains several repeated elements. Next, we pass the array to the array_unique function, which removes duplicate elements from the array and returns a new array $uniqueArray that does not contain duplicate elements. Finally, we print the contents of this new array using the print_r function.

Using the array_unique function can easily remove duplicate elements from a PHP array. However, it should be noted that this function can only remove elements with the same value. It cannot remove elements with the same key value but different key names.

Method 2: Manual deduplication

If we need to remove elements with the same key value but different key names in the array, or want to control the deduplication process more flexibly, we can use manual deduplication Methods. Here is a sample code:

<?php
$originalArray = array(1, 2, 3, 2, 4, 5, 3, 6);
$uniqueArray = array();
foreach($originalArray as $item) {
    if(!in_array($item, $uniqueArray)) {
        $uniqueArray[] = $item;
    }
}
print_r($uniqueArray);
?>

In the above code, we first create an original array $originalArray. Then we define an empty array $uniqueArray to store the results after deduplication. Next, we use a foreach loop to iterate through each element in the original array. For each element, we use the in_array function to determine whether it already exists in $uniqueArray. If it does not exist, the element is added to $uniqueArray; otherwise, the element is ignored. Finally, we use the print_r function to print the contents of $uniqueArray.

This method can control the deduplication process more flexibly, but it should be noted that it may not be as efficient as the array_unique function, especially when the original array is large.

Summary

This article introduces two methods to delete duplicate elements in PHP arrays, which are to use the array_unique function and manual deduplication. Both methods have their own advantages and disadvantages, and they need to be chosen according to the specific situation. In actual development, we can choose the appropriate method to deal with repeated elements in the array based on the characteristics of the data.

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