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PHP commonly used file operation function reference table_PHP tutorial

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Table a

Function

Description

Example

filesize

($file)

This function returns the size of a file in bytes. It is used to calculate how much space a file occupies on disk.

// get file owner and group
echo "uid: " . fileowner('myfile.html');
echo "gid: " . filegroup('myfile.html');
?>

fileatime

($file)

filemtime

($file)

These functions return the last time a file was accessed and modified respectively, and are used to find out whether a file has been modified after a specific date.

// get file access/modification times
echo "last accessed on: " . date("d-m-y", fileatime('myfile.html'));

echo "last modified on: " . date("d-m-y", filemtime('myfile.html'));
?>

fileperms

($file)

This function returns a file permission, use it to check whether the file is readable, writable or executable.

// get permissions in octal format
echo "file permissions: " . sprintf('%0', fileperms('myfile.html'));
?>

filetype

($file)

This function returns the "type" of the file - whether it is a connection, directory, attribute or block device, or a regular file. Use it to verify the nature of a file before performing an operation.

// get file type
echo "file type: " . filetype('myfile.html');
?>

stat($file)

This is a "catch-all" function that returns detailed statistics of a file, including its owner and group, size, last modification time, and number of index nodes. If you need comprehensive file statistics in a single function call, use this function instead of those listed previously.

// get file statistics
print_r(stat('myfile.html'));
?>

realpath

($file)

This function converts a relative file path to an absolute file path. This function is used when you need to find out the exact location of a file on the disk.

// get absolute path
// returns "/tmp/myfile.html"
echo "file path: " . realpath("./cook/book/http://www.cnblogs.com/myfile.html");
?>

basename

($file)

dirname

($file)

Given a complete file path, these functions break it into its component parts and return the file name and directory respectively.

// split directory and file names
// returns "/usr/local/bin"
echo "directory: " . dirname("/usr/local/bin/php");

// returns "php"
echo "file: " . basename("/usr/local/bin/php");
?>

file($file)

This function reads the contents of a file into an array. Each element in the array represents a line of file. This function is used to read the contents of the file into a variable for further processing.

// read file contents
$lines = file('myfile.html');

// print line by line
for($x=1; $x<=sizeof($lines); $x++) {
?echo "line $x: " . $lines[$x-1] . "n";
}
?>


www.bkjia.comtruehttp: //www.bkjia.com/PHPjc/445360.htmlTechArticleKeep reading and you will discover some new content! Table a Function Description Example filesize ($file) This function returns the size of a file in bytes. It is used to calculate the magnetic content of a file...
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