PHP pathinfo() Function: Syntax, Parameters, Return Values, and Practical Examples

The pathinfo() function in PHP returns information about a file path, such as directory name, base name, extension, and filename, either as an associative array or a string depending on the options supplied.

Its signature is mixed pathinfo(string $path[, int $options = PATHINFO_DIRNAME|PATHINFO_BASENAME|PATHINFO_EXTENSION|PATHINFO_FILENAME]) . If no $options are provided, the function returns an array containing dirname , basename , extension (if present), and filename .

The $path parameter specifies the file path to be parsed. The optional $options argument can be any combination of the constants PATHINFO_DIRNAME , PATHINFO_BASENAME , PATHINFO_EXTENSION , and PATHINFO_FILENAME to retrieve specific elements.

Example 1 demonstrates extracting each component from the path /www/htdocs/inc/lib.inc.php :

<?php
$path_parts = pathinfo('/www/htdocs/inc/lib.inc.php');
echo $path_parts['dirname'], "\n";
echo $path_parts['basename'], "\n";
echo $path_parts['extension'], "\n";
echo $path_parts['filename'], "\n";
?>

Output:

/www/htdocs/inc
lib.inc.php
php
lib

Example 2 shows behavior when the path has an empty or missing extension:

<?php
$path_parts = pathinfo('/path/emptyextension.');
var_dump($path_parts['extension']);
$path_parts = pathinfo('/path/noextension');
var_dump($path_parts['extension']);
?>

Output:

string(0) ""
Notice: Undefined index: extension in test.php on line 6
NULL

These examples illustrate how pathinfo() can be used to reliably dissect file paths in PHP scripts.