How to perform file operations in PHP7.0?

In the Internet era, file operations have become one of the most common operations for programmers. As a popular server-side scripting language, PHP also has powerful file operation functions.

This article will introduce how to perform file operations in PHP7.0, including operations such as opening, reading, writing, closing, and deleting files. At the same time, we will also introduce some common file processing functions to help readers better use PHP for file operations.

1. Open file

In PHP, our commonly used file opening function is fopen(). This function requires two parameters: file name and opening mode.

Open mode refers to the options available when opening a file. Common open modes are listed below:

• r: Read-only mode, the file pointer is at the head of the file.
• w: Write-only mode, create the file if it does not exist, clear the file if it exists.
• a: Append mode, if the file does not exist, create it, if the file exists, move the file pointer to the end of the file.
• x: Create a new file and open it in writing mode.
• b: Binary mode.
• t: Text mode.

The following is a simple example showing how to use the fopen() function to open a file named example.txt.

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

2. Reading files

There are many ways to read files. We introduce the use of the fread() function here.

This function requires two parameters: one is the file pointer, and the other is the number of bytes to read.

The following example will read the first 20 bytes from the file example.txt and then output it to the browser.

$myfile = fopen("example.txt", "r");
echo fread($myfile,20);
fclose($myfile);

3. Writing to a file

Writing to a file can also use the fopen() function. However, we need to use a different opening mode: w, a or x.

The following is an example that demonstrates how to open a file named example.txt and add a line of text to the end of it.

$myfile = fopen("example.txt", "a");
$txt = "Hello world
";
fwrite($myfile, $txt);
fclose($myfile);

4. Close the file

Just like opening the file, it is also important to close the file. In PHP, the function required to close a file is fclose().

The following is an example that demonstrates how to close a file named example.txt.

$myfile = fopen("example.txt", "r");
fclose($myfile);

5. Delete files

If we need to delete a file, we can use the unlink() function. This function requires one parameter, which is the name of the file to be deleted.

The following is an example that demonstrates how to delete a file named example.txt.

unlink("example.txt");

6. Commonly used file processing functions

• file_get_contents(): Read the entire file content at one time.
• file_put_contents(): Write the contents to the file.
• filesize(): Get the file size.
• rename(): Rename the file.
• copy(): Copy one file to another file.
• is_file(): Determine whether the file exists.
• is_dir(): Determine whether it is a directory.
• opendir(): Open the directory.
• readdir(): Read the directory.
• closedir(): Close the directory.

7. Conclusion

This article introduces some basic knowledge and common functions for file operations in PHP7.0. However, for file operations, there are many details that need to be paid attention to, such as exception handling, file permissions, etc. Programmers need to grasp them based on the actual situation.

Finally, we encourage readers to learn in depth PHP file operations in practice, continuously improve their programming skills, and lay a solid foundation for their careers.

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