Detailed explanation and examples of PHP file reading and writing operations

Detailed explanation and examples of PHP file read and write operations

1. Introduction
In the development process, it is often necessary to read and write files, such as reading configurations file, log file, etc., or write data to a file. PHP provides a wealth of file reading and writing functions. This article will introduce PHP's file reading and writing operations in detail and give some practical examples.

2. File reading operation

1. File reading function
   PHP provides multiple functions for file reading, the commonly used ones are: file_get_contents(), fopen (), fgets(), fread(), file(), etc. The following uses the file_get_contents() function as an example to demonstrate the file reading operation.

Code example:

$file = "example.txt";
$content = file_get_contents($file);
echo $content;

The above code will read the contents of the file named example.txt and output it to the page.

2. Read the file line by line
   Sometimes we need to read the file line by line and process each line. Functions for reading line by line are fgets() and fread(). The example is as follows:

Code example:

$file = "example.txt";
if ($handle = fopen($file, 'r')) {
    while (!feof($handle)) {
        $line = fgets($handle);
        echo $line."<br/>";
    }
    fclose($handle);
}

The above code will read the contents of the example.txt file line by line and output it to the page. Each line will be wrapped with the br tag. .

3. File writing operation

1. File writing function
   PHP provides multiple functions for file writing, the commonly used ones are: file_put_contents(), fopen (), fwrite(), etc. The following uses the file_put_contents() function as an example to demonstrate the file writing operation.

Code example:

$file = "example.txt";
$content = "Hello, World!";
file_put_contents($file, $content);

The above code will write "Hello, World!" to a file named example.txt. If the file does not exist, it will be created automatically; if the file already exists, the original content will be overwritten.

2. Append to write file
   Sometimes we need to append the content to an existing file instead of overwriting the original content. You can use the fopen() function to open a file with the "a" parameter and the fwrite() function for writing.

Code example:

$file = "example.txt";
$content = "Hello, World!";
if ($handle = fopen($file, 'a')) {
    fwrite($handle, $content);
    fclose($handle);
}

The above code will append "Hello, World!" to the end of the example.txt file.

4. File moving operation

1. File renaming
   PHP provides the rename() function, which can be used for file renaming operations.

Code example:

$oldFile = "example.txt";
$newFile = "new_example.txt";
rename($oldFile, $newFile);

The above code will rename the example.txt file to new_example.txt.

2. File movement
   File movement operations can be performed using the rename() function. The example is as follows:

Code example:

$sourceFile = "example.txt";
$destinationFolder = "uploads/";
$destinationFile = $destinationFolder . $sourceFile;

rename($sourceFile, $destinationFile);

The above code moves the example.txt file to the uploads folder.

5. Summary
This article introduces in detail the relevant knowledge and examples of PHP file read and write operations, including file reading, file writing, file movement and other operations. By using these functions, we can operate files more flexibly to meet the needs of the development process. I hope this article will help you gain an in-depth understanding of and use PHP file reading and writing operations.

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