freecodecamp--freecodecamp/curriculum/challenges/english/blocks/daily-coding-challenges-python/68ffb91507a5b645769328c8.md

id, title, challengeType, dashedName

id	title	challengeType	dashedName
68ffb91507a5b645769328c8	Challenge 105: Character Count	29	challenge-105

--description--

Given a sentence string, return an array with a count of each character in alphabetical order.

• Treat upper and lowercase letters as the same letter when counting.
• Ignore numbers, spaces, punctuation, etc.
• Return the count and letter in the format "letter count". For instance, "a 3".
• All returned letters should be lowercase.
• Do not return a count of letters that are not in the given string.

--hints--

count_characters("hello world") should return ["d 1", "e 1", "h 1", "l 3", "o 2", "r 1", "w 1"].

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(count_characters("hello world"), ["d 1", "e 1", "h 1", "l 3", "o 2", "r 1", "w 1"])`)
}})

count_characters("I love coding challenges!") should return ["a 1", "c 2", "d 1", "e 3", "g 2", "h 1", "i 2", "l 3", "n 2", "o 2", "s 1", "v 1"].

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(count_characters("I love coding challenges!"), ["a 1", "c 2", "d 1", "e 3", "g 2", "h 1", "i 2", "l 3", "n 2", "o 2", "s 1", "v 1"])`)
}})

count_characters("// TODO: Complete this challenge ASAP!") should return ["a 3", "c 2", "d 1", "e 4", "g 1", "h 2", "i 1", "l 3", "m 1", "n 1", "o 3", "p 2", "s 2", "t 3"].

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(count_characters("// TODO: Complete this challenge ASAP!"), ["a 3", "c 2", "d 1", "e 4", "g 1", "h 2", "i 1", "l 3", "m 1", "n 1", "o 3", "p 2", "s 2", "t 3"])`)
}})

--seed--

--seed-contents--

def count_characters(sentence):

    return sentence

--solutions--

def count_characters(sentence):
    from collections import Counter
    
    letters = [c.lower() for c in sentence if c.isalpha()]
    counts = Counter(letters)
    
    return [f"{letter} {counts[letter]}" for letter in sorted(counts)]