Solutions to inaccurate floating point operations under PHP
This article mainly introduces the solution to the inaccurate floating point operation under PHP. Interested friends can refer to it. I hope it will be helpful to everyone.
Are you doing one recently? The problem of addition and subtraction is that floating point operations are inaccurate. It seems that it is true that interpreted languages have problems with floating point operations.
First look at a piece of code:
<?php $a = 0.1; $b = 0.7; var_dump(($a + $b) == 0.8);
The printed value is actually boolean false
Why is this? The PHP manual has the following warning message for floating point numbers:
Warning
Floating point precision
Apparently simple decimal fractions like 0.1 or 0.7 cannot be converted to the internal binary format without losing a bit of precision. This can lead to confusing results: for example, floor((0.1 0.7)*10) will usually return 7 instead of the expected 8, because the internal representation of the result is something like 7.9999999999... .
This is related to the fact that it is impossible to express certain decimal fractions accurately with a limited number of digits. For example, 1/3 in decimal becomes 0.3333333. . .
So never believe that the floating point number result is accurate to the last digit, and never compare whether two floating point numbers are equal. If you really need higher precision, you should use arbitrary precision mathematical functions or gmp functions
Then the above calculation should be rewritten as
The above is the entire content of this article, I hope it will be helpful to everyone's learning.
Related recommendations:
PHP implements SQL statement formatting function
phpMethod to implement monomorphic design pattern
Method of TP5 Request request object in PHP
The above is the detailed content of Solutions to inaccurate floating point operations under PHP. For more information, please follow other related articles on the PHP Chinese website!

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.
