What behavior would you expect?

[Denis McMahon]

On Wed, 18 Feb 2015 21:44:12 -0700, Jason Friedman wrote:

> My question is, what would be a reasonable behavior/result/return value
> if:

> 1. "/path/to/dir" does not exist or is not readable 

Normally I'd say raise an exception. Whether you choose to use an 
existing exception (will trying to read a non existent dir raise one 
anyway?) or define your own is up to you. This condition would probably 
indicate an error in the data received by the function - you should be 
given a readable directory.

If (and only if) being called with an invalid directory is potentially 
valid, then you could respond to (1) the same as to (2).

> 2. no files match the given pattern

Return either None, 0, False or an empty string.

In both cases, it is then a matter for the calling code to catch the 
exception or handle the return value appropriately.

-- 
Denis McMahon, denismfmcmahon at gmail.com