I Used This Python One-Liner to List All Matching Files on My Computer

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Lazy as I am, I name all temporary code files code.py when I try something in Python. Today, once again, I needed to find one of my code.py files because of a code snippet I was interested in.

Being a Python enthusiast, I wondered:

πŸ‘‰ How can I find all files that match a certain pattern (e.g., a regular expression) using Python and only Python?

This quick tutorial will show you how I did it — I hope you’ll find some use in it as well.

Find All Files on My Windows Machine That Match Regex

This code uses the glob library to retrieve a list of all files in the Windows C directory and its subdirectories that match the query 'code.py'.

import glob

# Get the list of all files matching the query
file_list = glob.glob('C:\\**\\code.py', recursive=True)

# Print the resulting list

The recursive parameter is set to True which allows the glob library to search through all subdirectories. The file_list variable stores the list of all the files matching the query, and then it is printed out.

As a proof that I have a lot of code.py files on my computer—here’s the output on my Windows machine:

Ironically, the code itself runs in another code.py file — haha. πŸ€―πŸ˜†

Now, you may have some questions left:

What Does the Double Asterisk ** Mean?

The double asterisk (**) is a wildcard that allows for matching across multiple levels of a directory structure. Use it to match any number of subdirectories and/or files in a given directory.

Why Didn’t I Use a Single Asterisk *?

The single asterisk (*) is used to match a single level of a directory structure. It will only match subdirectories and/or files within the immediate directory. The double asterisk (**) allows for matching across multiple levels of a directory structure.

How to Match Other Regex Patterns?

The glob library allows you to use other regex patterns to match files.

You can use the question mark ? character to match any single character, the [ ] character class to match any single character in a set of characters, and the { } curly braces to match a set of multiple characters.

For example, the pattern 'C:\\**\\code[0-9].py' would match any file ending with 'code' followed by a single digit and ending with '.py'.

Why Did I Use The Double Backslash \\?

The double backslash (\\) is used as an escape character in Python. It indicates that the character following it should be treated as a literal character, rather than as a special character.

In this case, the double backslash indicates that the following characters should be treated as a literal path rather than as a special character.

What To Do On Linux?

On Linux, you can use the same glob library to match files. However, instead of using the double backslash (\\) to separate the directory levels, you will need to use the forward slash (/) instead.

For example, you could use the pattern 'my_dir/**/code.py' to match all files ending with 'code.py' in the my_dir directory and its subdirectories.

What To Do On macOS?

Same as on Linux — see the previous answer. πŸ‘†

Can I Learn More About Regular Expressions?

Sure, check out our full guide here:

πŸ‘‰ Python Regex Superpower — Ultimate Guide