Adding leading zeros to the integer part of filenames

Question

I have files generated, where the filenames contains within it an integer, but also has a prefix, like so:

snapshot_data_vss_iter_10000.caffemodel snapshot_data_vss_iter_1000.caffemodel snapshot_data_vss_iter_500.caffemodel

How do I pad the integers with leading zeros so I can use sort() later?

edit: I am aware of zfill() , but that requires me to split the string first to extract the integer part of it, pad it and then replace. I was wondering if there's a more pythonic way to do it

Thank you

Answer 1

I would suggest using formatting (which is nice with a format string):

>>> iters = 500
>>> f'snapshot_data_vss_iter_{iters:05}.caffemodel'
'snapshot_data_vss_iter_00500.caffemodel'

The :05 means to left pad to at least 5 characters using zeros. There are various other things you can do with string formatting, I'd suggest reading up .