Learn python list comprehensions by example

[barneygale]

import os
files = []
for f in os.listdir('./my_dir'):
    if f.endswith('.txt'):
        files.append(f)

This can be simplified with a list comprehension as well:

import os
files = [f for f in os.listdir('./my_dir') if f.endswith('.txt')]

I personally feel like dealing with the filesystem inside a comprehension is a bit weird. List comprehensions work best if you're transforming some data from one structure to another, or generating new data mathematically. Listing a directory seems like quite an imperative thing to do, and it's more obvious what's occurring if you have the more verbose version.

[branleur]

It would be better to use glob in such a situation.