freecodecamp--freecodecamp/curriculum/challenges/english/blocks/daily-coding-challenges-python/69f35a5bb823ed620fcb7cbd.md

id, title, challengeType, dashedName

id	title	challengeType	dashedName
69f35a5bb823ed620fcb7cbd	Challenge 284: I Before E	29	challenge-284

--description--

Given a word or sentence, return a corrected version where every word follows the "I before E except after C" rule.

• If a word contains "ei" not preceded by "c", replace it with "ie".
• If a word contains "ie" preceded by "c", replace it with "ei".
• All other words are left unchanged.

--hints--

i_before_e("beleive") should return "believe".

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(i_before_e("beleive"), "believe")`)
}})

i_before_e("recieve") should return "receive".

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(i_before_e("recieve"), "receive")`)
}})

i_before_e("we recieved a breif") should return "we received a brief".

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(i_before_e("we recieved a breif"), "we received a brief")`)
}})

i_before_e("she beleived the friendly niece could percieve the greif") should return "she believed the friendly niece could perceive the grief".

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(i_before_e("she beleived the friendly niece could percieve the greif"), "she believed the friendly niece could perceive the grief")`)
}})

i_before_e("we recieved relief after the theif gave us a breif piece of feirce deceit") should return "we received relief after the thief gave us a brief piece of fierce deceit".

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(i_before_e("we recieved relief after the theif gave us a breif piece of feirce deceit"), "we received relief after the thief gave us a brief piece of fierce deceit")`)
}})

--seed--

--seed-contents--

def i_before_e(sentence):

    return sentence

--solutions--

import re

def i_before_e(sentence):
    words = []
    for word in sentence.split(" "):
        word = re.sub(r"([^c])ei", r"\1ie", word)
        word = re.sub(r"cie", "cei", word)
        words.append(word)
    return " ".join(words)