PHP study notes: file operations and directory management

PHP study notes: File operation and directory management

In PHP, file operation and directory management are common and important functions. File operations allow us to read and write files, while directory management allows us to create, delete, and traverse directories. This article will introduce the basic knowledge of file operations and directory management in PHP, and provide specific code examples.

1. File operation

1.1 File creation and writing

In PHP, we can use the fopen() function to create or open a file , and use the fwrite() function to write the content to the file. The following is a sample code:

<?php
$filename = "test.txt";
$content = "Hello, world!";

$file = fopen($filename, "w");
fwrite($file, $content);

fclose($file);
?>

The above code first uses the fopen() function to create or open a file named test.txt, and specifies to open it in write mode. Then, use the fwrite() function to write the content "Hello, world!" to the file. Finally, use the fclose() function to close the file.

1.2 File Reading and Output

In addition to writing files, we can also use the fread() function to read the contents of the file and output it to the browser through the echo statement. The following is a sample code:

<?php
$filename = "test.txt";

$file = fopen($filename, "r");
$content = fread($file, filesize($filename));

echo $content;

fclose($file);
?>

The above code first uses the fopen() function to open the test.txt file created previously, and specifies that it should be opened in read-only mode. Then, use the fread() function to read the contents of the file and store it in the $content variable. Finally, use the echo statement to output the contents of the $content variable to the browser.

1.3 Copying and deleting files

In PHP, you can use the copy() function to copy a file to a specified directory. The following is a sample code:

<?php
$sourceFile = "test.txt";
$destinationDir = "backup/";

copy($sourceFile, $destinationDir . $sourceFile);
?>

The above code uses the copy() function to copy the test.txt file to a directory named backup.

In addition, we can also use the unlink() function to delete a file. The following is a sample code:

<?php
$filename = "test.txt";

if (file_exists($filename)) {
    unlink($filename);
    echo "文件删除成功！";
} else {
    echo "文件不存在！";
}
?>

The above code first uses the file_exists() function to check whether the file exists, and then uses the unlink() function to delete the file. If the file exists and is deleted successfully, "File deleted successfully!" will be output; if the file does not exist, "File does not exist!" will be output.

2. Directory management

2.1 Creation and deletion of directories

In PHP, we can use the mkdir() function to create a directory, use rmdir () function to delete a directory. The following is a sample code:

<?php
$dirname = "testdir";

mkdir($dirname);
echo "目录创建成功！";

rmdir($dirname);
echo "目录删除成功！";
?>

The above code creates a directory named testdir through the mkdir() function, and outputs "Directory creation successful!" through the echo statement. Then, the directory is deleted through the rmdir() function, and "Directory deletion successful!" is output.

2.2 Directory traversal and file search

In PHP, you can use the opendir() function to open a directory, and use the readdir() function to traverse the files and subdirectories in the directory. The following is a sample code:

<?php
$dirname = "testdir";

$dirHandle = opendir($dirname);

while (($file = readdir($dirHandle)) !== false) {
    echo $file . "<br>";
}

closedir($dirHandle);
?>

The above code first uses the opendir() function to open the previously created testdir directory, and stores the returned directory handle in the $dirHandle variable. Then, use a while loop and the readdir() function to iterate through the files and subdirectories in the directory and output the name of each file or subdirectory through an echo statement. Finally, use the closedir() function to close the directory handle.

In addition, we can use the glob() function to find files matching a specific pattern in a directory. The following is a sample code:

<?php
$dirname = "testdir";

$files = glob($dirname . "/*.txt");

foreach ($files as $file) {
    echo $file . "<br>";
}
?>

The above code uses the glob() function to find all files ending with .txt suffix in the testdir directory and store them in the $files array. Then, use a foreach loop to iterate through the array and output the name of each file through the echo statement.

Summary:

This article introduces the basic knowledge of file operations and directory management in PHP, and provides specific code examples. By learning and practicing this knowledge, we can better use PHP for file operations and directory management, and improve development efficiency. Hope these contents are helpful to everyone!

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