Python program to find files having a particular extension using RegEx

Prerequisite: Regular Expression in Python

Many of the times we need to search for a particular type of file from a list of different types of files. And we can do so with only a few lines of code using python. And the cool part is we don’t need to install any external package, python has a built-in package called re, with which we can easily write the program for performing this task.

Approach:

• This program searches for the files having “.xml” extension from a list of different files.
• Make a regular expression/pattern : “\.xml$”
• Here re.search() function is used to check for a match anywhere in the string (name of the file). It basically returns the match object when the pattern is found and if the pattern is not found it returns null.
• The functionality of different Metacharacters used here:

1.  \  It is used to specify a special meaning of character after it. It is also used to escape special characters.
2.  $ The string ends with the pattern which is before it.

Here “.xml” pattern is searched and processed.

Below is the implementation:

Python3

# import library
import re

# list of different types of file
filenames = ["gfg.html", "geeks.xml",
            "computer.txt", "geeksforgeeks.jpg"]

for file in filenames:
    # search given pattern in the line
    match = re.search("\.xml$", file)

    # if match is found
    if match:
        print("The file ending with .xml is:",
             file)

Output:

The file ending with .xml is: geeks.xml