Home Backend Development PHP Tutorial PHP file operation: reading files line by line

PHP file operation: reading files line by line

Aug 03, 2021 pm 05:09 PM
php document read file Read line by line

In the previous article "php file operation - reading files character by character" we introduced a method of reading files: reading files character by character. In this article, we will show you another way to read files: read the file line by line. Let's see how to read the file content line by line and output it. Let's learn together.

There is a text file named "test.txt", the contents of which are:

PHP file operation: reading files line by line

How do we read the contents of the file line by line and Output? Simple, today we will introduce two methods to you.

Method 1: Using the fgets() function

Let’s take a look at the code example:

1

2

3

4

5

6

7

8

9

10

11

<?php

header("Content-Type: text/html;charset=utf-8");    //设置字符编码

$handle = fopen(&#39;./test.txt&#39;, &#39;r&#39;);                 //打开文件

if (!$handle) {                                     //判断文件是否打开成功

    echo &#39;文件打开失败!&#39;;

}

while (false !== ($char = fgets($handle,1024))) {        //循环读取文件内容

    echo $char."<br>";

}

fclose($handle);                                    //关闭文件

?>

Copy after login

Output result:

PHP file operation: reading files line by line

Key function analysis:

fgets() function is used to read a line of data from an open file and accepts a required parameter $file (the file being opened) and an optional parameter $length (the number of bytes to be read); if the $length parameter is omitted, the default is to read Take 1k (i.e. 1024 bytes) length.

fgets() function encounters newline character, EOF (read to the end of the file) or reaches the specified length $length-1 Stop (the maximum length of the returned string is $length-1 bytes).

If we don't know how much data is in the file, we can use the filesize() function to get it, which can return the size of the specified file (number of bytes).

So the above code example can be modified:

1

2

3

4

5

6

7

8

9

10

11

12

13

<?php

header("Content-Type: text/html;charset=utf-8");    //设置字符编码

$url = &#39;./test.txt&#39;;

$handle = fopen($url, &#39;r&#39;);                 //打开文件

$size= filesize($url);                  //计算文件大小

if (!$handle) {                                     //判断文件是否打开成功

    echo &#39;文件打开失败!&#39;;

}

while (false !== ($char = fgets($handle,$size))) {        //循环读取文件内容

    echo $char."<br>";

}

fclose($handle);                                    //关闭文件

?>

Copy after login

The output result is the same as above.

Method 2: Using the fgetss() function

Let’s take a look at the code example:

1

2

3

4

5

6

7

8

9

10

11

<?php

header("Content-Type: text/html;charset=utf-8");    //设置字符编码

$handle = fopen(&#39;./test.txt&#39;, &#39;r&#39;);                 //打开文件

if (!$handle) {                                     //判断文件是否打开成功

    echo &#39;文件打开失败!&#39;;

}

while (false !== ($char = fgetss($handle,1024))) {        //循环读取文件内容

    echo $char."<br>";

}

fclose($handle);                                    //关闭文件

?>

Copy after login

Output result:

PHP file operation: reading files line by line

Key function analysis:

The fgetss() function is similar to the fgets() function. Both can read a line of data from the open file. The difference is fgetss() The function filters out HTML and PHP tags from the data.

fgetss() function accepts one required parameter $file, two optional parameters $length and $tags. The parameters $file and $length are introduced in the fgets() function. You can learn more about them above. The parameter $tags is used to specify which tags are not to be removed. Let’s learn more about it through an example:

PHP file operation: reading files line by line

1

2

3

4

5

6

7

8

9

10

11

<?php

header("Content-Type: text/html;charset=utf-8");    //设置字符编码

$handle = fopen(&#39;./test.txt&#39;, &#39;r&#39;);                 //打开文件

if (!$handle) {                                     //判断文件是否打开成功

    echo &#39;文件打开失败!&#39;;

}

while (false !== ($char = fgetss($handle,1024,"<h1>,<em>"))) {        //循环读取文件内容

    echo $char."<br>";

}

fclose($handle);                                    //关闭文件

?>

Copy after login

In the above code , we set the value of parameter $tags to "<h1>,<em></em> </h1>", that is, we do not filter <h1></h1> and <em></em> tag, so the output result is:

PHP file operation: reading files line by line

Note: After operating the file, remember to use the fclose() function to close the file!

Okay, that’s all. If you want to know anything else, you can click this. → →Basic operation of PHP files

## Recommended: PHP interview questions summary (collection)》《php video tutorial

The above is the detailed content of PHP file operation: reading files line by line. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website
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

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

PHP 8.4 Installation and Upgrade guide for Ubuntu and Debian 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

Explain JSON Web Tokens (JWT) and their use case in PHP APIs. 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,

How do you parse and process HTML/XML in PHP? 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::). 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.

PHP Program to Count Vowels in a String 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

What are PHP magic methods (__construct, __destruct, __call, __get, __set, etc.) and provide use cases? 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.

PHP and Python: Comparing Two Popular Programming Languages 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: A Key Language for Web Development 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

See all articles