Python program to find files having a particular extension using RegEx

In Python, you can efficiently identify files with a specific extension from a list of different file types using the built-in re module. This allows you to perform pattern matching without installing any external libraries. This article demonstrates how to find files with a particular extension (for example .xml) using regex.

Approach:

1. Define the regex pattern: To match .xml files, use the pattern: \.xml$

• \. -> Escapes the dot, since '.' has a special meaning in regex.
• xml -> Matches the literal characters xml.
• $ -> Ensures the pattern occurs at the end of the string.

2. Use re.search(): The re.search() function checks for a match anywhere in the string and returns a match object if found, otherwise, it returns None.

3. Loop through the files: Check each file name against the regex pattern and print the files that match the pattern.

Implementation

Output

The file ending with .xml is: geeks.xml

Explanation:

• fn = ["gfg.html", "geeks.xml", "computer.txt", "geeksforgeeks.jpg"]: Creates a list of file names with different extensions.
• for file in fn: Loops through each file name in the list.
• match = re.search(r"\.xml$", file): Uses regex to check if the file name ends with .xml.
  \. -> Escapes the dot.
  xml -> Matches the literal characters xml.
  $ -> Ensures .xml is at the end of the string.

Note: This method works for any file extension by simply changing the regex pattern.

Related Articles:

• Python - Loop through files of certain extensions
• Open a File by Regular Expression in Python