label_letters_example.py

import re

addrs = [
    'PetImages/A/test1.jpg',
    'PetImages/B/test3.jpg',
    'PetImages/B/test3.jpg',
    'PetImages/C/test4.jpg',
    'PetImages/D/test2.jpg',
    'PetImages/C/test4.jpg',
    'PetImages/A/test1.jpg',
    'PetImages/D/test2.jpg'
]

letterString = 'ABCDEFGHJKLMNOPQRSTUVWXYZ'

labels = []
for addr in addrs:
    m = re.match('PetImages/([A-Z])/.*', addr)
    labels.append(letterString.find(m.group(1)))

print labels

labels.append(letterString.find(m.group(1)))
AttributeError: 'NoneType' object has no attribute 'group'
Also getting this error if following your code

Hi Shazuka.

Sorry for not responding earlier. I must have missed this comment.

If you get the problem that the match is a NoneType that means that the regular expression might not match.

Is the path to the files correct?

The regular expression i use above is 'PetImages/([A-Z])/.*'

That requires that you have a set of paths starting with PetImages then the directory inside there should be a uppercase letter and the files inside those directories can have any name.

You can make it more specific by chaning it to say 'PetImages/([A-Z])/[a-zA-Z]+.jpg'

Then you only allowing names with letters a to z and A to Z ending with jpg.

If you think regular expressions are strange I have a video that might help
https://www.youtube.com/watch?v=tXhwgHXH8OM

Best regards
Daniel

Hi @kalaspuffar. I am trying out this code for around 40 classes, however my label names are not single letters such A,B,C. They have such names as character_1_ka. As i understand, the letterString looks at each character of the string as a label, yes? Would this be fixed by creating an array of strings as letterString?