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Classifying letters as vowels or consonants and counting their frequencies (Python recipe) by Vasudev Ram
ActiveState Code (http://code.activestate.com/recipes/580749/)

This recipe shows how to take a string as input and classify the characters in it as vowels, consonants or neither. The frequency of each vowel is calculated and the frequency of all the consonants in total is calculated. The program logic is fairly simple, and uses a dictionary comprehension and a dict; the more interesting thing about it, is that it illustrates 8 Python language features in under 35 lines of code.

More details and sample output here:

https://jugad2.blogspot.in/2017/01/classifying-letters-and-counting-their.html

Python, 44 lines
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# classify_letters1.py

# Author: Vasudev Ram
# Copyright 2017 Vasudev Ram
# Web site: https://vasudevram.github.io
# Blog: https://jugad2.blogspot.com
# Product store: https://gumroad.com/vasudevram

# Classify input chars as vowels or consonants.
# Count frequencies of each vowel.
# Count total frequency of all consonants together.

import string

VOWELS = 'aeiou'

def classify_letters(input):
    vowel_freqs = { vowel: 0 for vowel in VOWELS }
    consonants = 0
    for c in input:
        if not (c in string.ascii_lowercase):
            continue
        if c in VOWELS:
            vowel_freqs[c] = vowel_freqs.get(c, 0) + 1
        else:
            consonants += 1
    return vowel_freqs, consonants

# Letter frequencies in s increase sequentially from 1 for both 
# vowels and consonants, separately.
s = ''.join(['a' * 1, 'b' * 1, 'c' * 2, 'd' * 3, 'e' * 2, 'f' * 4, \
    'g' * 5, 'h' * 6, 'i' * 3, 'j' * 7, 'k' * 8, 'l' * 9, 'm' * 10, \
    'n' * 11, 'o' * 4, 'p' * 12, 'q' * 13, 'r' * 14, 's' * 15, \
    't' * 16, 'u' * 5, 'w' * 17, 'y' * 18, 'z' * 19])

print "Classifying letters in string:", s
print '-' * 70
vowel_freqs, consonants = classify_letters(s)
print 'vowel freqs:', vowel_freqs
print 'consonants total freq:', consonants
print '-' * 70
print 'Checking results:'
assert len(s) == sum(vowel_freqs.values()) + consonants
print 'OK'
Tags: assertions, comprehension, dict, dictionaries, dict_comp, python, python2, tuple, unpack