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
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
1672
14
1428
52
1332
25
1276
29
1256
24
PHP vs. Python: Understanding the Differences
Apr 11, 2025 am 12:15 AM
PHP and Python each have their own advantages, and the choice should be based on project requirements. 1.PHP is suitable for web development, with simple syntax and high execution efficiency. 2. Python is suitable for data science and machine learning, with concise syntax and rich libraries.
PHP: A Key Language for Web Development
Apr 13, 2025 am 12:08 AM
PHP is a scripting language widely used on the server side, especially suitable for web development. 1.PHP can embed HTML, process HTTP requests and responses, and supports a variety of databases. 2.PHP is used to generate dynamic web content, process form data, access databases, etc., with strong community support and open source resources. 3. PHP is an interpreted language, and the execution process includes lexical analysis, grammatical analysis, compilation and execution. 4.PHP can be combined with MySQL for advanced applications such as user registration systems. 5. When debugging PHP, you can use functions such as error_reporting() and var_dump(). 6. Optimize PHP code to use caching mechanisms, optimize database queries and use built-in functions. 7
PHP and Python: Comparing Two Popular Programming Languages
Apr 14, 2025 am 12:13 AM
PHP and Python each have their own advantages, and choose according to project requirements. 1.PHP is suitable for web development, especially for rapid development and maintenance of websites. 2. Python is suitable for data science, machine learning and artificial intelligence, with concise syntax and suitable for beginners.
PHP in Action: Real-World Examples and Applications
Apr 14, 2025 am 12:19 AM
PHP is widely used in e-commerce, content management systems and API development. 1) E-commerce: used for shopping cart function and payment processing. 2) Content management system: used for dynamic content generation and user management. 3) API development: used for RESTful API development and API security. Through performance optimization and best practices, the efficiency and maintainability of PHP applications are improved.
The Enduring Relevance of PHP: Is It Still Alive?
Apr 14, 2025 am 12:12 AM
PHP is still dynamic and still occupies an important position in the field of modern programming. 1) PHP's simplicity and powerful community support make it widely used in web development; 2) Its flexibility and stability make it outstanding in handling web forms, database operations and file processing; 3) PHP is constantly evolving and optimizing, suitable for beginners and experienced developers.
PHP and Python: Different Paradigms Explained
Apr 18, 2025 am 12:26 AM
PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.
PHP vs. Other Languages: A Comparison
Apr 13, 2025 am 12:19 AM
PHP is suitable for web development, especially in rapid development and processing dynamic content, but is not good at data science and enterprise-level applications. Compared with Python, PHP has more advantages in web development, but is not as good as Python in the field of data science; compared with Java, PHP performs worse in enterprise-level applications, but is more flexible in web development; compared with JavaScript, PHP is more concise in back-end development, but is not as good as JavaScript in front-end development.
PHP and Python: Code Examples and Comparison
Apr 15, 2025 am 12:07 AM
PHP and Python have their own advantages and disadvantages, and the choice depends on project needs and personal preferences. 1.PHP is suitable for rapid development and maintenance of large-scale web applications. 2. Python dominates the field of data science and machine learning.
