calling upper() on a string, not working?

[Larry Bates]

John Salerno wrote:
> Can someone tell me what's happening here. This is my code:
> 
> 
> 
> PUNCT_SPACE_SET = set(string.punctuation + string.whitespace)
> 
> def filter_letters(original):
>     return ''.join(set(original) - PUNCT_SPACE_SET)
> 
> 
> 
> 'original' is a string. The above works as expected, but when I change
> it to
> 
> return ''.join(set(original.upper()) - PUNCT_SPACE_SET)
> 
> it doesn't seem to work. The full code is below if it helps to understand.
> 
> 
> 
> import string
> import random
> import itertools
> 
> PUNCT_SPACE_SET = set(string.punctuation + string.whitespace)
> 
> def convert_quote(quote):
>     return encrypt_quote(quote).split('|')
> 
> def encrypt_quote(original):
>     original_letters = filter_letters(original)
>     new_letters = list(string.ascii_uppercase)
>     while True:
>         random.shuffle(new_letters)
>         trans_letters = ''.join(new_letters)[:len(original_letters)]
>         if test_code(original_letters, trans_letters):
>             trans_table = string.maketrans(original_letters, trans_letters)
>             break
>     return original.translate(trans_table)
> 
> def filter_letters(original):
>     return ''.join(set(original) - PUNCT_SPACE_SET)
>     #return ''.join(set(original.upper()) - PUNCT_SPACE_SET)
> 
> def test_code(original_letters, trans_letters):
>     for pair in itertools.izip(original_letters, trans_letters):
>         if pair[0] == pair[1]:
>             return False
>     return True
> 
> if __name__ == '__main__':
>     print convert_quote("The past is not dead. In fact, it's not even
> past.|William Faulkner")

Not exactly sure why you think its not working.  When you create a set
from the original.upper() you get a smaller number of characters because
you no longer get both 'T' and 't' as well as 'I' and 'i' as you do in
the lower case version of the string.

>>> set(original.split('|')[0])
set(['a', ' ', 'c', 'e', 'd', "'", 'f', 'i', 'h', ',', 'o', 'n', 'p', 's', 'T',
'v', 'I', '.', 't'])
>>> set(original.split('|')[0].upper())
set(['A', ' ', 'C', 'E', 'D', "'", 'F', 'I', 'H', ',', 'O', 'N', 'P', 'S', 'T',
'V', '.'])
>>>

sets can only contain "unique" entries.  Letters that are repeated only get
added once.  When you do .upper() you convert lowercase 't' to 'T' and lower
case 'i' to 'I' so that letter only gets added to the set a single time.

Hope info helps.

Larry Bates