PHP gets string length function strlen() function
In some website registrations or other activities, we need users to submit some information, and there will be certain requirements for this information. For example, there are some restrictions on the length of user registration information, which cannot be less than or greater than this. Here we need to use PHP's own functions to perform the acquisition operation.
The strlen() function is used to obtain the string length. Let’s talk about the syntax and application of the strlen() function.
strlen() function is mainly used to obtain the length of the specified string string.
The syntax format is as follows:
strlen(string);
Parameter: string The string whose length needs to be calculated.
Return value: Generally, the length of the string is returned. If the string is empty, the return value is 0.
Use the strlen() function to get the length of the string. The sample code is as follows:
<?php $str='字a符1串b长2度'; echo strlen($str).'<br>'; //长度为19 ?>
The output result is: 19
Result Analysis:
When the strlen character length is used, a UTF8 Chinese character is counted as three lengths, and numbers, English, decimal point, underline and space occupy one character, so "character a is 1 and string b is long 2 The length of "degree" is 3+1+3+1+3+1+3+1+3=19.
It should be noted that in gb2312, when strlen calculates the character length, one Chinese character only counts 2 lengths.
The strlen() function can be used to detect the length of a string in addition to obtaining the length of the string.
The following is a simple example to use the strlen() function to detect the length of the submitted user password. If the password length is less than 5, a prompt message will pop up.
The specific steps are as follows:
1. Create a new PHP file and name it index.php.
2. Add a form and set the form's action attribute to test.php.
3. Use HTML tags to design a form, add a username text box and name it user; add a password text box and name it pwd.
<html>
<body>
<form action="test.php" method="post">
user :<input type="text" name="username"><br />
pwd :<input type="password" name="pwd"><br />
<input type="submit" name="submit" value="提交" />
</form>
</body>
</html>4. In addition, create a PHP file, named test.php, and write the following code in it:
<?php
if(strlen($_POST['pwd'])<6) //测试用户密码的长度是否小于5
{
// 不符合要求则弹出该信息
echo "<script>alert('密码不能小于5位!请重新输入 ');history.back();</script>";
}
?>In the above code, it is through the POST method (about the POST method, you can View in PHP Chinese website) Receives the user password string entered by the user. Use the strlen() function to obtain the length of the password entered by the user, and use the if conditional control statement to judge the length of the user's password. If the password entered by the user does not reach the specified length, a prompt box message will pop up.
The above is the detailed content of PHP gets string length function strlen() function. 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
AI Hentai Generator
Generate AI Hentai for free.
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
1378
52
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
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
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 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 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
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.
