PHP Loops - Understanding and Using While Loops-PHP Tutorial-php.cn

Home

Backend Development

PHP Tutorial

PHP Loops - Understanding and Using While Loops

jacklove

May 07, 2018 am 11:35 AM

phpwhileuse

PHP Loop - While loop plays an important role in php, this article will give some explanations about it.

PHP Loops

When you write code, you often need to have the same block of code run over and over again. We can use loop statements in our code to accomplish this task.

In PHP, the following loop statements are provided:

while - As long as the specified condition is true, the code block will be executed in a loop

do...while - Executed once block of code, and then repeats the loop when the specified condition is true

for - Loops to execute the code block a specified number of times

foreach - Based on array Loop through each element in the code block

while loop

The while loop will repeatedly execute the code block until the specified condition is not true.

Syntax

while (condition){
Code to be executed;}

Example

The following example first sets the variable i The value is 1 ($i=1;).

Then, as long as i is less than or equal to 5, the while loop will continue to run. Each time the loop runs, i will be incremented by 1:

<html><body><?php
$i=1;while($i<=5){
    echo "The number is " . $i . "<br>";
    $i++;}?></body></html>

Output:

The number is 1
The number is 2
The number is 3
The number is 4
The number is 5

do...while statement

do...while statement will execute the code at least once, then check the condition, and repeat as long as the condition is true cycle.

Syntax

do{
    要执行的代码;}while (条件);

Example

The following example first sets the value of variable i to 1 ($i=1;).

Then, start the do...while loop. The loop increments the value of variable i by 1 and then outputs it. First check the condition (i is less than or equal to 5), as long as i is less than or equal to 5, the loop will continue to run:

<html><body><?php
$i=1;do{
    $i++;
    echo "The number is " . $i . "<br>";}while ($i<=5);?></body></html>

Output:

The number is 2
The number is 3
The number is 4
The number is 5
The number is 6

This article provides some detailed explanations of php loops and while loops for more learning Please follow the php Chinese website to view the information.

Related recommendations:

Detailed explanation of php magic variable usage examples, detailed explanation of php magic examples_PHP tutorial

The above is the detailed content of PHP Loops - Understanding and Using While Loops. 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

How does PHP type hinting work, including scalar types, return types, union types, and nullable types?Apr 17, 2025 am 12:25 AM

PHP type prompts to improve code quality and readability. 1) Scalar type tips: Since PHP7.0, basic data types are allowed to be specified in function parameters, such as int, float, etc. 2) Return type prompt: Ensure the consistency of the function return value type. 3) Union type prompt: Since PHP8.0, multiple types are allowed to be specified in function parameters or return values. 4) Nullable type prompt: Allows to include null values and handle functions that may return null values.

How does PHP handle object cloning (clone keyword) and the __clone magic method?Apr 17, 2025 am 12:24 AM

In PHP, use the clone keyword to create a copy of the object and customize the cloning behavior through the \_\_clone magic method. 1. Use the clone keyword to make a shallow copy, cloning the object's properties but not the object's properties. 2. The \_\_clone method can deeply copy nested objects to avoid shallow copying problems. 3. Pay attention to avoid circular references and performance problems in cloning, and optimize cloning operations to improve efficiency.

PHP vs. Python: Use Cases and ApplicationsApr 17, 2025 am 12:23 AM

PHP is suitable for web development and content management systems, and Python is suitable for data science, machine learning and automation scripts. 1.PHP performs well in building fast and scalable websites and applications and is commonly used in CMS such as WordPress. 2. Python has performed outstandingly in the fields of data science and machine learning, with rich libraries such as NumPy and TensorFlow.

Describe different HTTP caching headers (e.g., Cache-Control, ETag, Last-Modified).Apr 17, 2025 am 12:22 AM

Key players in HTTP cache headers include Cache-Control, ETag, and Last-Modified. 1.Cache-Control is used to control caching policies. Example: Cache-Control:max-age=3600,public. 2. ETag verifies resource changes through unique identifiers, example: ETag: "686897696a7c876b7e". 3.Last-Modified indicates the resource's last modification time, example: Last-Modified:Wed,21Oct201507:28:00GMT.

Explain secure password hashing in PHP (e.g., password_hash, password_verify). Why not use MD5 or SHA1?Apr 17, 2025 am 12:06 AM

In PHP, password_hash and password_verify functions should be used to implement secure password hashing, and MD5 or SHA1 should not be used. 1) password_hash generates a hash containing salt values to enhance security. 2) Password_verify verify password and ensure security by comparing hash values. 3) MD5 and SHA1 are vulnerable and lack salt values, and are not suitable for modern password security.

PHP: An Introduction to the Server-Side Scripting LanguageApr 16, 2025 am 12:18 AM

PHP is a server-side scripting language used for dynamic web development and server-side applications. 1.PHP is an interpreted language that does not require compilation and is suitable for rapid development. 2. PHP code is embedded in HTML, making it easy to develop web pages. 3. PHP processes server-side logic, generates HTML output, and supports user interaction and data processing. 4. PHP can interact with the database, process form submission, and execute server-side tasks.

PHP and the Web: Exploring its Long-Term ImpactApr 16, 2025 am 12:17 AM

PHP has shaped the network over the past few decades and will continue to play an important role in web development. 1) PHP originated in 1994 and has become the first choice for developers due to its ease of use and seamless integration with MySQL. 2) Its core functions include generating dynamic content and integrating with the database, allowing the website to be updated in real time and displayed in personalized manner. 3) The wide application and ecosystem of PHP have driven its long-term impact, but it also faces version updates and security challenges. 4) Performance improvements in recent years, such as the release of PHP7, enable it to compete with modern languages. 5) In the future, PHP needs to deal with new challenges such as containerization and microservices, but its flexibility and active community make it adaptable.

Why Use PHP? Advantages and Benefits ExplainedApr 16, 2025 am 12:16 AM

The core benefits of PHP include ease of learning, strong web development support, rich libraries and frameworks, high performance and scalability, cross-platform compatibility, and cost-effectiveness. 1) Easy to learn and use, suitable for beginners; 2) Good integration with web servers and supports multiple databases; 3) Have powerful frameworks such as Laravel; 4) High performance can be achieved through optimization; 5) Support multiple operating systems; 6) Open source to reduce development costs.

See all articles

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

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)

1 months agoBy尊渡假赌尊渡假赌尊渡假赌

R.E.P.O. Best Graphic Settings

1 months agoBy尊渡假赌尊渡假赌尊渡假赌

Assassin's Creed Shadows: Seashell Riddle Solution

2 weeks agoByDDD

R.E.P.O. How to Fix Audio if You Can't Hear Anyone

1 months agoBy尊渡假赌尊渡假赌尊渡假赌

R.E.P.O. Chat Commands and How to Use Them

1 months agoBy尊渡假赌尊渡假赌尊渡假赌

Hot Tools

mPDF

mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),