Count letters in a text file

Question

I am a beginner python programmer and I am trying to make a program which counts the numbers of letters in a text file. Here is what I've got so far:

import string 
text = open('text.txt')
letters = string.ascii_lowercase
for i in text:
  text_lower = i.lower()
  text_nospace = text_lower.replace(" ", "")
  text_nopunctuation = text_nospace.strip(string.punctuation)
  for a in letters:
    if a in text_nopunctuation:
      num = text_nopunctuation.count(a)
      print(a, num)

If the text file contains hello bob, I want the output to be:

b 2
e 1
h 1
l 2
o 2

My problem is that it doesn't work properly when the text file contains more than one line of text or has punctuation.

Answer 1

This is very readable way to accomplish what you want using Counter:

from string import ascii_lowercase
from collections import Counter

with open('text.txt') as f:
    print Counter(letter for line in f 
                  for letter in line.lower() 
                  if letter in ascii_lowercase)

You can iterate the resulting dict to print it in the format that you want.

Answer 2

You have to use collections.Counter

from collections import Counter
text = 'aaaaabbbbbccccc'
c = Counter(text)
print c

It prints:

Counter({'a': 5, 'c': 5, 'b': 5})

Your text variable should be:

import string
text = open('text.txt').read()
# Filter all characters that are not letters.
text = filter(lambda x: x in string.letters, text.lower())

For getting the output you need:

for letter, repetitions in c.iteritems():
    print letter, repetitions

In my example it prints:

a 5
c 5
b 5

For more information Counters doc