I have a problem concerning a comparison between a char key in a dict and a char within a list. The Task is to read a text and count all beginning letters.
I have a list with chars:
bchars = ('i','g','h','n','h')
and a dict with the alphabet and frequency default to zero:
d = dict(dict())
for i in range(97,123):
d[i-97]={chr(i):0}
no i want to check like the following:
for i in range(len(bchars)):
for j in range(len(d)):
if(bchars[i] in d[j]):
d[j][chr(i+97)] +=1
else:
d[j][chr(i+97)] +=0
so if the char in the list is a key at the certain position then += 1 else += zero I thought by using a if/else statement I can bypass the KeyError.
Is there any more elegant solution for that?
The specific problem is that you check whether bchars[i] is in d[j], but then the key you actually use is chr(i+97).
chr(i+97) is the index of the ith character in bchars, but mapped to ASCII characters starting from 'a'. Why would you want to use this as your key?
I think you really want to do:
for i in range(len(bchars)):
for j in range(len(d)):
if(bchars[i] in d[j]):
d[j][bchars[i]] += 1
else:
d[j][bchars[i]] = 1
Note that you can't use += in the else; remember how you literally just checked whether the key was there and decided it wasn't?
More broadly, though, your code doesn't make sense - it is overcomplicated and does not use the real power of Python's dictionaries. d looks like:
{0: {'a': 0}, 1: {'b': 0}, 2: {'c': 0}, ...}
It would be much more sensible to build a dictionary mapping character directly to count:
{'a': 0, 'b': 0, 'c': 0, ...}
then you can simply do:
for char in bchars:
if char in d:
d[char] += 1
Python even comes with a class just for doing this sort of thing.