Count frequency of letters in a text file [closed]

Answer 1

This way creates a dictionary histogram for each character, which could be used to create a bar chart or similar. If you want to limit it to letters or some subset, you'll need to add an extra conditional, or filter freqs at the end.

freqs = {}
with open('your_filename.txt') as f:
    for line in f:
        for char in line:
            if char in freqs:
                freqs[char] += 1
            else:
                freqs[char] = 1

print(freqs)

You can also write the same logic using dict.setdefault:

freqs = {}
with open('your_filename.txt') as f:
    for line in f:
        for char in line:
            freqs.setdefault(char, 0)
            freqs[char] += 1

Or using collections.defaultdict:

from collections import defaultdict

freqs = defaultdict(int)
with open('your_filename.txt') as f:
    for line in f:
        for char in line:
            freqs[char] += 1

Answer 2

basically, without imports: is_letter is a function to decide if something is a letter, so that you can count other things than the usual english letters

def add_or_init(dictionary, c):
        if(c in dictionary):
                dictionary[c]+=1
        else:
                dictionary[c]=1
def count_one_letter(dictionary, c, is_letter):
        if is_letter(c):
                add_or_init(dictionary, c)
def count_letters(dictionary, string, is_letter):
        for c in string:
                count_one_letter(dictionary, c, is_letter)
        return dictionary

#count all characters
count_letters(dict(),'aaabbbcccffffd eee fff ggg',lambda x: True)
# => {'a': 3, ' ': 3, 'c': 3, 'b': 3, 'e': 3, 'd': 3, 'g': 3, 'f': 3}

Answer 3

Use collections.Counter():

from collections import Counter
with open(file) as f:
    c = Counter()
    for line in f:
        c += Counter(line)

If the file is not so large, you can read all of it into memory as a string and convert it into a Counter object in one line of code:

c = Counter(f.read())

Example:

>>> c = Counter()
>>> c += Counter('aaabbbcccffffd eee fff ggg')
>>> c
Counter({'a': 3, ' ': 3, 'c': 3, 'b': 3, 'e': 3, 'd': 3, 'g': 3, 'f': 3})
>>> c += Counter('aaabbbccc')
Counter({'a': 6, 'c': 6, 'b': 6, ' ': 3, 'e': 3, 'd': 3, 'g': 3, 'f': 3})

or use the count() method of strings:

from string import ascii_lowercase     # ascii_lowercase =='abcdefghijklmnopqrstuvwxyz'
with open(file) as f:
    text = f.read().strip()
    dic = {}
    for x in ascii_lowercase:
        dic[x] = text.count(x)

Answer 4

Counter is a good way to do this, but Counter is only available in 3.1 and up, plus 2.7.

If you're on 3.0 or 2.[56], you probably should use collections.defaultdict(int) instead.

Answer 5

Use a dictionary - basically letters[char]++