How can I check a filename suffix against a lot of options tersely?

Question

I’m trying to write a program that essentially divides different file types among different directories. My computer does have many different image file types, so it makes a very long line in my code:

if file.name.endswith(".jpg") or 
   file.name.endswith(".JPG") or 
   file.name.endswith(".jpeg") or 
   file.name.endswith(".JPEG") or 
   file.name.endswith(".heic") or 
   file.name.endswith(".HEIC") or 
   file.name.endswith(".png") or 
   file.name.endswith(".PNG") or 
   file.name.endswith(".avif") or 
   file.name.endswith(".AVIF"):

I tried putting all the file type strings into a list and using the any() function but the problem is that any() gives a boolean output, while the file.name.endswith() function requires a str input.

Any ideas on how to simplify this line?

Asked By: baby

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Source

Answer 1

os.path.splitext() can split the extension off a filename, and using lower() can avoid the need to handle differently-cased variants separately:

valid_extensions = set(['.jpg', '.jpeg', '.heic', '.png', '.avif'])

def check_extension(filename):
    return os.path.splitext(filename)[1].lower() in valid_extensions

This works as:

>>> check_extension('good.JPEG')
True
>>> check_extension('bad.zip')
False

Answered By: Charles Duffy

Answer 2

Based on your use of file.name, I’m guessing file is probably a Path object. If so, in addition to the name attribute, it also has a suffix which contains the file extension (and stem, which is the part of the filename before the extension and can come in handy for other things). Once you have the suffix, you can lower-case it and check for its membership in a set (which is more efficient than checking membership in, for example, a list).

if file.suffix.lower() in {'.jpg', '.jpeg', '.heic', '.png', '.avif'}:

Answered By: CrazyChucky

Answer 3

str.endswith() accepts a tuple of strings and any match is True. Also use str.lower() so you don’t need to check for upper and lower case separately.

if file.name.lower().endswith((".jpg", ".jpeg", ".heic", ".png", ".avif")):

Answered By: kindall

How can I check a filename suffix against a lot of options tersely?

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