Backend Development
PHP Problem
PHP function application to check whether a value is finite, infinite or non-numeric
PHP function application to check whether a value is finite, infinite or non-numeric
In the previous article "PHP function application: start executing the program after pausing for a few seconds", we learned about the method of delaying the execution of the current script to a specified time (how many seconds later). This time we continue to learn PHP functions and introduce how to check whether a given value is a finite value, an infinite value or a non-numeric value. Interested friends can learn about it~
The main point of this article The content is: Check whether a value is finite, infinite or non-numeric.
1: Check whether a value is a finite value
You can use the is_finite($value) function to determine a valuevalueWhether it is a limited value. If the specified value is a finite value, the function returns true or 1; otherwise, it returns false/nothing. A value is finite if it is within the range allowed by PHP floating point numbers on the native platform.
Let’s take a closer look at the following example:
<?php
header("content-type:text/html;charset=utf-8");
function isFinite($value){
if(is_finite($value)){
echo $value."是有限值。<br>";
}else{
echo $value."不是有限值。<br>";
}
}
isFinite(2);
isFinite(log(0));
?>log(0)The value is -INF, INF refers to infinity, And -INF is negative infinity; therefore log(0) is not a finite value. Therefore the output result:
Two: Check whether a value is infinite
You can use is_infinite($value) Function to determine whether a value value is infinite. If the specified value is a finite value, the function returns TRUE or 1; otherwise, it returns FALSE (no output). The value is infinite if it is within the range allowed by PHP floating point numbers on the native platform.
Let’s take a look at the following example in detail:
<?php
header("content-type:text/html;charset=utf-8");
function isInfinite($value){
if(is_infinite($value)){
echo $value."是无限值。<br>";
}else{
echo $value."不是无限值。<br>";
}
}
isInfinite(2);
isInfinite(log(0));
?>Output result:
Three: Check whether a value is Non-numeric
You can use the is_nan($value) function to determine whether a value is non-numeric. If the specified value is non-numeric, the function returns true or 1; otherwise, it returns false/nothing.
Let’s take a closer look at the following example:
<?php
header("content-type:text/html;charset=utf-8");
function isNan($value){
if(is_nan($value)){
echo "是非数值。<br>";
}else{
echo "不是非数值。<br>";
}
}
isNan(2);
isNan(NAN);
isNan(acos(1.01));
?>NaN (Not a Number, not a number) is a type of value of numeric data type in computer science, which represents undefined or unrepresentable value. Often used in floating point operations. We can use the is_nan() function to check if a value is NaN.
In the above example , acos(1.01) will return NaN, so the calculation result of acos(1.01) is a non-numeric value. Therefore, the output result is:
Okay, that’s all. If you want to know anything else, you can click this. → →php video tutorial
The above is the detailed content of PHP function application to check whether a value is finite, infinite or non-numeric. 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 Installation and Upgrade guide for Ubuntu and Debian
Dec 24, 2024 pm 04:42 PM
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
7 PHP Functions I Regret I Didn't Know Before
Nov 13, 2024 am 09:42 AM
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
How To Set Up Visual Studio Code (VS Code) for PHP Development
Dec 20, 2024 am 11:31 AM
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
Explain JSON Web Tokens (JWT) and their use case in PHP APIs.
Apr 05, 2025 am 12:04 AM
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,
PHP Program to Count Vowels in a String
Feb 07, 2025 pm 12:12 PM
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
How do you parse and process HTML/XML in PHP?
Feb 07, 2025 am 11:57 AM
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
Explain late static binding in PHP (static::).
Apr 03, 2025 am 12:04 AM
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 PHP magic methods (__construct, __destruct, __call, __get, __set, etc.) and provide use cases?
Apr 03, 2025 am 12:03 AM
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.
