Finding duplicate file names and modifying them based on elements of the path

[Peter Otten]

Larry.Martell at gmail.com wrote:

> It seems that if you do a list(group) you have consumed the list. This
> screwed me up for a while, and seems very counter-intuitive.

Many itertools functions work that way. It allows you to iterate over the 
items even if there is more data than fits into memory. 
If you need to keep all items and are sure that your computer can cope with 
them at once you can always throw in a

group = list(group)