How to delete duplicate data from array in php

When developing with PHP, you often need to operate on arrays. Among them, removing duplicate data from an array is a common task. This article will introduce how to use PHP to remove duplicate data from an array.

In PHP, there are two ways to remove duplicate elements in an array: using a loop and using a PHP function.

Use a loop to delete duplicate elements in an array

Use a loop statement to traverse all elements in an array and determine whether they are duplicated. If duplicate, the element is removed from the array.

The following is a sample code that uses a loop to delete duplicate elements in an array:

$my_array = array(1, 2, 3, 2, 4, 3, 5, 1);
$new_array = array();
foreach ($my_array as $value) {
    if (!in_array($value, $new_array)) {
        $new_array[] = $value;
    }
}
print_r($new_array);

In the above code, we first define a primitive array $my_array, which contains some duplicate elements. We use a foreach loop to iterate through each element in the array.

In the loop, we use the in_array() function to check whether the current element is in the new array $new_array. If the element does not exist, the element is added to the new array $new_array.

Finally, output the contents of the new array to get the result after deduplication.

Use PHP functions to delete duplicate elements from an array

In addition to the basic loop method, PHP also provides some built-in functions to delete duplicate elements.

①array_unique() function

array_unique() function can remove duplicate elements in the array and return the remaining elements. The following is a sample code that uses the array_unique() function to delete duplicate elements in an array:

$my_array = array(1, 2, 3, 2, 4, 3, 5, 1);
$new_array = array_unique($my_array);
print_r($new_array);

In the above code, we define a primitive array $my_array, and then use the array_unique() function to delete duplicate elements. Finally, output the contents of the new array to get the deduplicated result.

②array_keys() and array_values() functions

The array_keys() function can return all key names in the array, and the array_values() function can return all key values ​​​​in the array. These two functions can be used to delete duplicate elements in an array. The implementation code is as follows:

$my_array = array(1, 2, 3, 2, 4, 3, 5, 1);
$new_array = array_values(array_unique($my_array));
print_r($new_array);

In the above code, we first use the array_unique() function to remove duplicate elements, and then use the array_values() function to return all the values ​​of the new array.

Finally, output the contents of the new array to get the result after deduplication.

Summary

In PHP, removing duplicate elements from an array is a common task. We can use loop statements or built-in functions to achieve this goal. For large arrays, it is more efficient to use built-in functions, while for small arrays, loop statements provide better control of the flow. No matter which method you use, care needs to be taken to keep the code readable and maintainable.

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