Pythonic way for double iteration (list all files with extensions)

Given a base path and a list with extensions the task is to list all files:

Two of my solutions are:

from glob import glob
from os import path

EXTENSIONS = ['*.zip', '*.jar', '*.pdf']
DOC_PATH = '/path/to/files'

# Solution1:
files = []         
for ext in EXTENSIONS:
    files.extend(glob(path.join(DOC_PATH, ext)))
# works but looks very clumsy

# Solution2:
files = reduce(lambda x,y: x+y,
               [glob(path.join(DOC_PATH, ext)) for ext in EXTENSIONS])
# Also functional but looks like a misuse of reduce

Have you got any other ideas?

If you only need to iterate over them (once) and not an actual list, you could use itertools.chain and glob.iglob:

files = chain(*(iglob(path.join(DOC_PATH, ext)) for ext in EXTENSIONS))

If you do need an actual list, you can further call list(files), of course.

StackExchange Code Review Q#56332, answer score: 3