This article mainly introduces the usage skills of each and list functions in PHP. Interested friends can refer to it. I hope it will be helpful to everyone.
1. Usage of each
Let’s look at the API first
array each (array &$array)
This is described in the api: each - returns the current key/value pair in the array and moves the array pointer forward one step
Let's first take a look at what the returned array looks like Like?
<?php $arr = array('你','若','安','好','便','是','晴','天'); print_r(each($arr)); print_r(each($arr)); echo '<hr />'; /* 返回 Array ( [1] => 你 [value] => 你 [0] => 0 [key] => 0 ) Array ( [1] => 若 [value] => 若 [0] => 1 [key] => 1 ) */ //执行相同的一段代码,从‘你'到‘若',说明each是会每执行一次,游标向数组尾部移动一步 //0和Key存放的是键 //1和value存放的是值 //因此each满足遍历数组的,得到当前的键和值,以及每执行一次,向尾部移动一步游标 //因此循环数组也可以用each这么写 reset($arr); for(;$tmp=each($arr);){ echo $tmp[0],'~',$tmp[1],'<br />'; } /* 返回 0~你 1~若 2~安 3~好 4~便 5~是 6~晴 7~天 */ ?>
2. How to use list
Let’s first look at what the api says
Like array(), this Not really functions, but language constructs. list() uses one step to assign values to a set of variables.
Let’s look at an example:
<?php list($a,$b)=array(10,20); echo $a,'~',$b,'<br />'; //返回10~20 ?>
Yes, you can assign values to a set of variables
Let’s look at another example:
<?php list($a,$b,,$c)=array(2=>10,3=>20,4=>30,1=>40); echo $a,'~',$b,'~',$c,'<br />'; //返回notice~40~20 //执行到$a的时候返回给我一个notice:说数组没有0键 ?>
According to the general idea, it should Will return: 10~20~40
Why will this notice~40~20 be returned?
Answer: This involves the operating mechanism of the list. This is how the list is assigned
First of all: ignore the array on the right and look at the variables in the List. From left to right it should be $a = arr[0] $b=arr[1] $c=arr[3]
Then: start assigning values from right to left, the order of assignment is $c=arr[3] $b=arr[1 ] $a=arr[0]
So $c=20 $b = 40 Because there is no arr[0], $a gave a warning
3 .Use each and list to implement array traversal
<?php $arr = array('你','若','安','好','便','是','晴','天'); for(;list($k,$v)=each($arr);){ echo $k,'~',$v,'<br />'; } /* return: 0~你 1~若 2~安 3~好 4~便 5~是 6~晴 7~天 */ ?>
Summary: The above is the entire content of this article, I hope it can be helpful to everyone Learning helps.
Related recommendations:
PHP session session processing function example detailed explanation
php A simple method to implement process control switch
Summary of methods for generating short URLs in PHP
The above is the detailed content of Tips on using each and list functions in PHP. For more information, please follow other related articles on the PHP Chinese website!

The article discusses PHP Data Objects (PDO), an extension for database access in PHP. It highlights PDO's role in enhancing security through prepared statements and its benefits over MySQLi, including database abstraction and better error handling.

Memcache and Memcached are PHP caching systems that speed up web apps by reducing database load. A single instance can be shared among projects with careful key management.

Article discusses steps to create and manage MySQL databases using PHP, focusing on connection, creation, common errors, and security measures.

The article discusses how JavaScript and PHP interact indirectly through HTTP requests due to their different environments. It covers methods for sending data from JavaScript to PHP and highlights security considerations like data validation and prot

The article discusses executing PHP scripts from the command line, including steps, common options, troubleshooting errors, and security considerations.

PEAR is a PHP framework for reusable components, enhancing development with package management, coding standards, and community support.

PHP is a versatile scripting language used mainly for web development, creating dynamic pages, and can also be utilized for command-line scripting, desktop apps, and API development.

The article discusses PHP's evolution from "Personal Home Page Tools" in 1995 to "PHP: Hypertext Preprocessor" in 1998, reflecting its expanded use beyond personal websites.


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

WebStorm Mac version
Useful JavaScript development tools

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
Powerful PHP integrated development environment

SublimeText3 Chinese version
Chinese version, very easy to use

PhpStorm Mac version
The latest (2018.2.1) professional PHP integrated development tool
