PHP Example Tutorial: File Reading and Writing Operation Guide

PHP Example Tutorial: File Reading and Writing Operation Guide

Introduction:
File operation is one of the very basic and commonly used skills in Web development. In PHP, file reading and writing are one of the common operations in the PHP development process. This article will introduce file reading and writing operations in PHP, and explain its specific implementation methods in detail through code examples.

1. File reading operation

1. Open the file

In PHP, we can use the fopen() function to Open a file. This function accepts two parameters: file name and open mode.

$filename = "example.txt";
$handle = fopen($filename, "r");

In this example, we open a text file named example.txt and assign the file handle to the $handle variable. Open mode r indicates read-only mode.

2. Read the file content

Next, we can use the fgets() function to read the file content line by line and add the read Each row is stored in a variable.

while ($line = fgets($handle)) {
    echo $line;
}

In this example, we use the fgets() function to read a line in the file pointed to by the file handle $handle and copy it Stored in the $line variable. Then we use the echo statement to output the read content.

3. Close the file

After the file reading is completed, we need to use the fclose() function to close the file.

fclose($handle);

This function closes the file pointed to by file handle $handle.

2. File writing operation

1. Opening a file

Similar to file reading, we can use fopen() Function to open a file for writing. Just set the opening mode to w or a.

$filename = "example.txt";
$handle = fopen($filename, "w");

In this example, we open a text file named example.txt and store the file handle into the $handle variable. Open mode w indicates write mode, which will clear the file content and rewrite it.

If we want to append to the end of the file with existing content, we can use the open mode a.

2. Write file content

Next, we can use the fwrite() function to write content to the file.

$content = "Hello, World!";
fwrite($handle, $content);

In this example, we use the fwrite() function to write the string Hello, World! to the file handle$handle in the file pointed to.

3. Close the file

After the file is written, we also need to use the fclose() function to close the file.

fclose($handle);

This function will close the file pointed to by the file handle $handle.

Summary:
Through the above examples, we have learned the basic operation methods of file reading and writing in PHP. Mastering these skills, we can easily handle file reading and writing needs during PHP development. At the same time, we can also expand and optimize these basic operations according to actual development needs to further improve development efficiency.

Reference code example:

// 文件读取示例
$filename = "example.txt";
$handle = fopen($filename, "r");
while ($line = fgets($handle)) {
    echo $line;
}
fclose($handle);

// 文件写入示例
$filename = "example.txt";
$handle = fopen($filename, "w");
$content = "Hello, World!";
fwrite($handle, $content);
fclose($handle);

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