PHP Advanced File Read and Write Operations Tutorial

In the above code, we define the file name example.txt, then use the file_get_contents() function to read the file's content into the string $content. Next, we use the echo statement to output the content to the browser.

2.2 Read a File Line by Line

Sometimes, we need to read a file's contents line by line. To do this, we can use the fopen() and fgets() functions. The fopen() function opens the file, while fgets() reads the file line by line. Here’s an example:

$filename = "example.txt";
$file = fopen($filename, "r");
if ($file) {
    while (($line = fgets($file)) !== false) {
        echo $line;
    }
    fclose($file);
}

In the above code, we open the file example.txt using fopen() and specify read mode ("r"). We then enter a while loop where the fgets() function reads each line of the file and stores it in the $line variable. The loop continues until the entire file is read or an error occurs. Finally, we use fclose() to close the file.

3. File Write Operations

3.1 Write to an Entire File

In PHP, the simplest way to write to an entire file is to use the file_put_contents() function, which writes a string to a file in one go. Here's how to use it to write to a file:

$filename = "example.txt";
$content = "Hello, world!";
file_put_contents($filename, $content);

In the above code, we define the file name example.txt and the content Hello, world!, then use file_put_contents() to write the content to the file. If the file doesn't exist, it will be automatically created.

3.2 Write to a File Line by Line

Writing to a file line by line is similar to reading a file line by line. We can use the fopen() and fputs() functions for this task. Here's an example:

$filename = "example.txt";
$content = array("Hello", "world", "!");
$file = fopen($filename, "w");
if ($file) {
    foreach ($content as $line) {
        fputs($file, $line . "\n");
    }
    fclose($file);
}

In the above code, we define the file name example.txt and the content array $content. We then open the file with the fopen() function and specify write mode ("w"). Next, we loop through the content array, using fputs() to write each line, appending a newline character. Finally, we use fclose() to close the file.

4. Conclusion

In this article, we covered various PHP methods for reading and writing files, including how to read an entire file, read a file line by line, and write to a file both as a whole and line by line. These operations are useful in many real-world applications, such as file uploads and file handling. Mastering these techniques will help you efficiently handle file operations and expand the capabilities of PHP in web development.