Find Unique Characters in a File

Question

I have a file with 450,000+ rows of entries. Each entry is about 7 characters in length. What I want to know is the unique characters of this file.

For instance, if my f

Answer 1

s=open("text.txt","r").read()
l= len(s)
unique ={}
for i in range(l):
 if unique.has_key(s[i]):
  unique[s[i]]=unique[s[i]]+1
 else:
  unique[s[i]]=1
print unique