


php array_flip() and array_uniqure() remove duplicate elements from array_PHP tutorial
There are several functions to delete duplicate elements from an array in PHP. One is array_unique() and the other is array_flip() and array_uniqure() functions, but the latter is several times more performant than the former, so I will only introduce the two. to remove duplicate array elements.
The method is as follows:
The code is as follows | Copy code | ||||||||
|
What is going on? Let’s look at the function of array_flip(): array_flip() is used to exchange the key and value of each element of an array, such as:
The code is as follows | Copy code | ||||
$arr1 = array("age" => 30, "name" => 'Happy Garden');
$arr2 = array_flip($arr1); // $arr2 is array(30 => "age", 'Happy Garden' => "name"); |
In a PHP array, different elements are allowed to take the same value, but the same key name is not allowed to be used by different elements, such as:
The code is as follows | Copy code | ||||
$arr1 = array("age" => 30, "name" => 'Happy Garden', "age" => 20); "age" => 2 0 will replace "age" => 30
$arr1 = array("name" => 'Happy Garden', "age" => 45); |
So, we can know why array_flip(array_flip($arr)) can delete duplicate elements in the array. First, the value in $arr will become a key name, because the value is repeated. After becoming a key name, these repeated values will become duplicate key names. The PHP engine will delete the duplicate key names and only keep the last one. . Such as:
代码如下 | 复制代码 |
function delmember(&$array, $id) { $size = count($array); for($i = 0; $i <$size - $id - 1; $i ++) { $array[$id + $i] = $array[$id + $i + 1]; } unset($array[$size - 1]); } |
The code is as follows | Copy code |
<🎜>$arr1 = array("age" => 30, "name" => 'Happy Garden', "age" => 20); $arr1 = array_flip($arr1); // $arr1 becomes array("Happy Garden" => "name", 20 => "age"); //Restore the key name and value of $arr1: $arr1 = array_flip($arr1); |
The code is as follows | Copy code |
function delmember(&$array, $id) { $size = count($array); for($i = 0; $i <$size - $id - 1; $i ++) <🎜> { <🎜> $array[$id + $i] = $array[$id + $i + 1]; <🎜> } <🎜> unset($array[$size - 1]); <🎜> } <🎜> |
//使用例子:
代码如下
| 复制代码 | ||||
delsame($output);
while(list($key, $value) = each($output))
{
echo "$key:$value"."
";
}
//方法二
function uniquearray($array)
reset($u_array, 1); for ($i=0,$n=count($u_array, 1);$i<$n;$i ) {
Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics

PHP 8.4 brings several new features, security improvements, and performance improvements with healthy amounts of feature deprecations and removals. This guide explains how to install PHP 8.4 or upgrade to PHP 8.4 on Ubuntu, Debian, or their derivati

If you are an experienced PHP developer, you might have the feeling that you’ve been there and done that already.You have developed a significant number of applications, debugged millions of lines of code, and tweaked a bunch of scripts to achieve op

Visual Studio Code, also known as VS Code, is a free source code editor — or integrated development environment (IDE) — available for all major operating systems. With a large collection of extensions for many programming languages, VS Code can be c

JWT is an open standard based on JSON, used to securely transmit information between parties, mainly for identity authentication and information exchange. 1. JWT consists of three parts: Header, Payload and Signature. 2. The working principle of JWT includes three steps: generating JWT, verifying JWT and parsing Payload. 3. When using JWT for authentication in PHP, JWT can be generated and verified, and user role and permission information can be included in advanced usage. 4. Common errors include signature verification failure, token expiration, and payload oversized. Debugging skills include using debugging tools and logging. 5. Performance optimization and best practices include using appropriate signature algorithms, setting validity periods reasonably,

A string is a sequence of characters, including letters, numbers, and symbols. This tutorial will learn how to calculate the number of vowels in a given string in PHP using different methods. The vowels in English are a, e, i, o, u, and they can be uppercase or lowercase. What is a vowel? Vowels are alphabetic characters that represent a specific pronunciation. There are five vowels in English, including uppercase and lowercase: a, e, i, o, u Example 1 Input: String = "Tutorialspoint" Output: 6 explain The vowels in the string "Tutorialspoint" are u, o, i, a, o, i. There are 6 yuan in total

This tutorial demonstrates how to efficiently process XML documents using PHP. XML (eXtensible Markup Language) is a versatile text-based markup language designed for both human readability and machine parsing. It's commonly used for data storage an

Static binding (static::) implements late static binding (LSB) in PHP, allowing calling classes to be referenced in static contexts rather than defining classes. 1) The parsing process is performed at runtime, 2) Look up the call class in the inheritance relationship, 3) It may bring performance overhead.

What are the magic methods of PHP? PHP's magic methods include: 1.\_\_construct, used to initialize objects; 2.\_\_destruct, used to clean up resources; 3.\_\_call, handle non-existent method calls; 4.\_\_get, implement dynamic attribute access; 5.\_\_set, implement dynamic attribute settings. These methods are automatically called in certain situations, improving code flexibility and efficiency.
