php remove duplicate elements from array

PHP is a powerful web development language that provides many array functions to process data. When we need to remove duplicate elements from an array, we can easily accomplish this task using some built-in functions of PHP. This article will introduce how to use PHP built-in functions to remove duplicate elements from an array.

1. Using the array_unique() function

PHP’s array_unique() function is one of the most commonly used methods to remove duplicate elements from an array. This function returns a new array containing all the distinct elements from the original array.

The following is an example of using the array_unique() function to delete duplicate elements in an array:

<?php
$fruits = array("apple", "banana", "orange", "apple", "orange");
$result = array_unique($fruits);
print_r($result);
?>

Output result:

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

As you can see, the duplicate elements in the original array are "apple " and "orange" were removed.

2. Use the array_values() function

Using the array_unique() function will return a new array, and the index keys will be reordered. If we need to preserve the keys of the original array, we can reindex the array using PHP's array_values() function.

The following is an example of using the array_values() function:

<?php
$fruits = array("apple", "banana", "orange", "apple", "orange");
$result = array_unique($fruits);
$result = array_values($result);
print_r($result);
?>

Output result:

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

It can be seen that after using the array_values() function, the keys of the new array have been Reordered.

3. Using foreach loop

We can also use PHP's foreach loop and in_array() function to delete duplicate elements in the array. The idea of ​​this method is: loop through each element in the array, if it already exists in the new array, skip it, otherwise add it to the new array.

The following is an example of using a foreach loop to delete duplicate elements in an array:

<?php
$fruits = array("apple", "banana", "orange", "apple", "orange");
$result = array();

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

print_r($result);
?>

Output result:

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

As you can see, this method can also successfully delete elements in the array Repeating elements.

Summary:

PHP provides a variety of built-in functions to process arrays, including functions for removing duplicate elements from arrays. The array_unique() function is one of the most commonly used methods and it returns a new array containing all the distinct elements from the original array. If we need to preserve the keys of the original array, we can reindex the array using PHP's array_values() function. We can also use foreach loop and in_array() function to remove duplicate elements from the array. Either method can help us easily solve the problem of deleting duplicate elements in an array.

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