How do I read the number of files in a folder using Python?

You can use the glob module:

>>> import glob
>>> print len(glob.glob('/tmp/*'))
10

Or, as Mark Byers suggests in his answer, if you only want files:

>>> print [f for f in glob.glob('/tmp/*') if os.path.isfile(f)]
['/tmp/foo']
>>> print sum(os.path.isfile(f) for f in glob.glob('/tmp/*'))
1

Mark Byer’s answer is simple, elegant, and goes along with the python spirit.

There’s a problem, however: if you try to run that for any other directory than ".", it will fail, since os.listdir() returns the names of the files, not the full path. Those two are the same when listing the current working directory, so the error goes undetected in the source above.

For example, if you are at /home/me and you list /tmp, you’ll get (say) ['flashXVA67']. You’ll be testing /home/me/flashXVA67 instead of /tmp/flashXVA67 with the method above.

You can fix this using os.path.join(), like this:

import os.path
path = './whatever'
count = len([f for f in os.listdir(path) if os.path.isfile(os.path.join(path, f))])

Also, if you’re going to be doing this count a lot and require performance, you may want to do it without generating additional lists. Here’s a less elegant, unpythonesque yet efficient solution:

import os

def fcount(path):
    """ Counts the number of files in a directory """
    count = 0
    for f in os.listdir(path):
        if os.path.isfile(os.path.join(path, f)):
            count += 1
            
    return count


# The following line prints the number of files in the current directory:
path = "./whatever"
print fcount(path)

total = len(filter(
            lambda f: os.path.isfile(os.path.join(path_to_dir, f)),
            os.listdir(path_to_dir)))

OR

total = sum([True for f in os.listdir(path_to_dir) if os.path.isfile(os.path.join([path_to_dir, f)])

pathlib, that is new in v. 3.4, makes like easier. The line labelled 1 makes a non-recursive list of the current folder, the one labelled 2 the recursive list.

from pathlib import Path

import os
os.chdir('c:/utilities')

print (len(list(Path('.').glob('*')))) ## 1
print (len(list(Path('.').glob('**/*')))) ## 2

There are more goodies too. With these additional lines you can see both the absolute and relative file names for those items that are files.

for item in Path('.').glob('*'):
    if item.is_file():
        print (str(item), str(item.absolute()))

Result:

boxee.py c:utilitiesboxee.py
boxee_user_catalog.sqlite c:utilitiesboxee_user_catalog.sqlite
find RSS.py c:utilitiesfind RSS.py
MyVideos34.sqlite c:utilitiesMyVideos34.sqlite
newsletter-1 c:utilitiesnewsletter-1
notes.txt c:utilitiesnotes.txt
README c:utilitiesREADME
saveHighlighted.ahk c:utilitiessaveHighlighted.ahk
saveHighlighted.ahk.bak c:utilitiessaveHighlighted.ahk.bak
temp.htm c:utilitiestemp.htm
to_csv.py c:utilitiesto_csv.py

recursive solution:

sum(len(fs) for _,_,fs in os.walk(os.getcwd()))

for current directory solution:

len(os.walk(os.getcwd()).next()[2])

Try this:

import os
for dirpath, dirnames, filenames in os.walk('./your/folder/path'):
    print(f'There are {len(dirnames)} directories and {len(filenames)} images in {dirpath}.')

The result would look like this:

There are 10 directories and 0 images in ./asl_data/photos.
There are 0 directories and 32 images in ./asl_data/photos.
There are 0 directories and 34 images in ./asl_data/photos1.
There are 0 directories and 32 images in ./asl_data/photos2.
There are 0 directories and 31 images in ./asl_data/photos3.
There are 0 directories and 34 images in ./asl_data/photos4.
There are 0 directories and 31 images in ./asl_data/photos5.
There are 0 directories and 40 images in ./asl_data/photos6.
There are 0 directories and 33 images in ./asl_data/photos7.
There are 0 directories and 30 images in ./asl_data/photos8.
There are 0 directories and 39 images in ./asl_data/photos9.