How to delete duplicate elements in one-dimensional array in php

In the PHP development process, array is a very commonly used data structure. Since arrays can store any type of data, arrays play a very important role when operating on data. However, when operating on arrays, we may encounter a common problem, that is, how to remove duplicate elements in an array. This article will introduce how to use PHP language to delete duplicate elements in a one-dimensional array.

First of all, we need to make it clear that PHP provides many methods to delete duplicate elements in an array, including using for loops, using the array_unique function, and using the array_diff function. The steps for using these three methods will be introduced below.

Method 1: Use for loop

Using for loop to delete duplicate elements in an array is a very basic method. The specific steps are as follows:

1. Define a Empty array, used to store arrays without duplicate elements;
2. Get each element in the original array and compare it with the elements in the new array;
3. If there is no element in the new array , the element is added to the new array.

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

<?php
$arr = array(1, 2, 3, 3, 4, 4, 5);
$new_arr = array();
for($i = 0; $i < count($arr); $i++){
    if(!in_array($arr[$i], $new_arr)){
        $new_arr[] = $arr[$i];
    }
}
print_r($new_arr);
?>

Method 2: Use the array_unique function

Use the array_unique function to easily delete For repeated elements in the array, the specific steps are as follows:

1. Pass the array as a parameter to the array_unique function;
2. Get an array without repeated elements through the return value of the array_unique function.

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

<?php
$arr = array(1, 2, 3, 3, 4, 4, 5);
$new_arr = array_unique($arr);
print_r($new_arr);
?>

Method 3: Using the array_diff function

Using the array_diff function can also delete arrays The difference is that this function can handle the difference set relationship between the two arrays. The specific steps are as follows:

1. Take the original array as the first parameter;
2. Use the array_unique function to remove duplicates as the second parameter;
3. Get an array without duplicate elements through the return value of the array_diff function.

Here is a code example that uses the array_diff function to remove duplicate elements from an array:

<?php
$arr = array(1, 2, 3, 3, 4, 4, 5);
$unique_arr = array_unique($arr);
$new_arr = array_diff($arr, $unique_arr);
print_r($new_arr);
?>

Removing duplicate elements from an array is very simple no matter which method you use. Choosing the appropriate method according to the actual situation can effectively improve the efficiency of the PHP program, while also making the program easier to maintain and upgrade. I hope this article can be helpful to everyone when using PHP to delete duplicate elements in one-dimensional arrays in actual development.

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