[Tutor] Filename match on file extensions

Steven D'Aprano steve at pearwood.info
Wed Oct 3 07:49:07 CEST 2012

On Wed, Oct 03, 2012 at 03:14:16AM +0000, Dave Wilder wrote:
> Hello,
> Below is a snippet of a search I want to do for any file that contains the string "quarantine" in the filename.
> It works for picking up any file name containing "quarantine" except when "quarantine" is used as an extension.

Incorrect. It only picks up filenames that *begin* with "quarantine". 
The critical code is:

i.lower().find("quarantine".lower()) == 0

which matches:


but not


The correct test for matching anywhere in the string is:

   "quarantine" in i.lower()

By the way, it is misleading to call your loop variable "i". By 
convention, i is used for integer loop variables. Since your loop 
variable in this case is a file name, I would name it "filename":

for filename in files:
    if "quarantine" in filename.lower():

Also, you might consider using the "glob" module, which is good for 
finding filenames matching so-called globs:


matches file names starting with quarantine, ending with .txt, and 
anything at all in between.


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