search
HomeBackend DevelopmentPHP ProblemPHP removes duplicate elements from one-dimensional array

For a one-dimensional array, if there are duplicate elements, removing these duplicate elements is a common requirement in programming. In PHP we can achieve this in several ways. This article will introduce several commonly used methods.

Method 1: Use the array_unique function

The array_unique function is a function that comes with PHP and can easily remove duplicate elements from the array. It can be used not only for one-dimensional arrays, but also for multi-dimensional array deduplication operations.

Sample code:

$array = array('a', 'b', 'c', 'a', 'd', 'c');
$array_unique = array_unique($array);
print_r($array_unique);

Output result:

Array
(
    [0] => a
    [1] => b
    [2] => c
    [4] => d
)

It is very simple to use the array_unique function to remove duplicate elements. However, it should be noted that the array_unique function can only remove duplicate elements with the same value, but not duplicate elements with the same key value.

Method 2: Use loop traversal

Another way to remove duplicates is to use a loop to traverse the array, comparing each element with the elements after it one by one. If the same elements are found, Remove it.

Sample code:

$array = array('a', 'b', 'c', 'a', 'd', 'c');
$count = count($array);
for($i=0;$i<$count;$i++){
    for($j=$i+1;$j<$count;$j++){
        if($array[$i] == $array[$j]){
            unset($array[$j]);
        }
    }
}
print_r($array);

Output result:

Array
(
    [0] => a
    [1] => b
    [2] => c
    [4] => d
)

Using the loop traversal method can also easily achieve duplication, but when the array is relatively large, the performance may be affected Influence.

Method 3: Use array_flip and array_values ​​functions

This method uses PHP's built-in array_flip function, which can interchange the keys and values ​​of the array. In this way, if the original array has duplicate values, the swapped array will have duplicate keys, and only the last one will be retained, and the rest will be automatically overwritten.

Then, we use the array_values ​​function to re-index the reordered array and remove the key-value correspondence, thereby obtaining the deduplicated array.

Sample code:

$array = array('a', 'b', 'c', 'a', 'd', 'c');
$array_flip = array_flip($array);
$array_unique = array_values($array_flip);
print_r($array_unique);

Output result:

Array
(
    [0] => a
    [1] => b
    [2] => c
    [3] => d
)

The advantage of this method is that it can quickly remove duplicates and retain the order of the original array. However, it only works for one-dimensional arrays whose values ​​are strings, and unexpected results will occur for other types of data (such as arrays, objects, etc.).

To sum up, for removing duplicate elements from a one-dimensional array, we can use the array_unique function that comes with PHP, or we can use the loop traversal method or the array_flip and array_values ​​functions. Depending on actual needs and data types, choosing a method that suits you can improve the efficiency and readability of your code.

The above is the detailed content of PHP removes duplicate elements from one-dimensional array. For more information, please follow other related articles on the PHP Chinese website!

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
ACID vs BASE Database: Differences and when to use each.ACID vs BASE Database: Differences and when to use each.Mar 26, 2025 pm 04:19 PM

The article compares ACID and BASE database models, detailing their characteristics and appropriate use cases. ACID prioritizes data integrity and consistency, suitable for financial and e-commerce applications, while BASE focuses on availability and

PHP Secure File Uploads: Preventing file-related vulnerabilities.PHP Secure File Uploads: Preventing file-related vulnerabilities.Mar 26, 2025 pm 04:18 PM

The article discusses securing PHP file uploads to prevent vulnerabilities like code injection. It focuses on file type validation, secure storage, and error handling to enhance application security.

PHP Input Validation: Best practices.PHP Input Validation: Best practices.Mar 26, 2025 pm 04:17 PM

Article discusses best practices for PHP input validation to enhance security, focusing on techniques like using built-in functions, whitelist approach, and server-side validation.

PHP API Rate Limiting: Implementation strategies.PHP API Rate Limiting: Implementation strategies.Mar 26, 2025 pm 04:16 PM

The article discusses strategies for implementing API rate limiting in PHP, including algorithms like Token Bucket and Leaky Bucket, and using libraries like symfony/rate-limiter. It also covers monitoring, dynamically adjusting rate limits, and hand

PHP Password Hashing: password_hash and password_verify.PHP Password Hashing: password_hash and password_verify.Mar 26, 2025 pm 04:15 PM

The article discusses the benefits of using password_hash and password_verify in PHP for securing passwords. The main argument is that these functions enhance password protection through automatic salt generation, strong hashing algorithms, and secur

OWASP Top 10 PHP: Describe and mitigate common vulnerabilities.OWASP Top 10 PHP: Describe and mitigate common vulnerabilities.Mar 26, 2025 pm 04:13 PM

The article discusses OWASP Top 10 vulnerabilities in PHP and mitigation strategies. Key issues include injection, broken authentication, and XSS, with recommended tools for monitoring and securing PHP applications.

PHP XSS Prevention: How to protect against XSS.PHP XSS Prevention: How to protect against XSS.Mar 26, 2025 pm 04:12 PM

The article discusses strategies to prevent XSS attacks in PHP, focusing on input sanitization, output encoding, and using security-enhancing libraries and frameworks.

PHP Interface vs Abstract Class: When to use each.PHP Interface vs Abstract Class: When to use each.Mar 26, 2025 pm 04:11 PM

The article discusses the use of interfaces and abstract classes in PHP, focusing on when to use each. Interfaces define a contract without implementation, suitable for unrelated classes and multiple inheritance. Abstract classes provide common funct

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)
3 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
R.E.P.O. Best Graphic Settings
3 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
R.E.P.O. How to Fix Audio if You Can't Hear Anyone
3 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
WWE 2K25: How To Unlock Everything In MyRise
3 weeks agoBy尊渡假赌尊渡假赌尊渡假赌

Hot Tools

MantisBT

MantisBT

Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

ZendStudio 13.5.1 Mac

ZendStudio 13.5.1 Mac

Powerful PHP integrated development environment

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

PhpStorm Mac version

PhpStorm Mac version

The latest (2018.2.1) professional PHP integrated development tool

SecLists

SecLists

SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.