Solving CS50P - Problem Set 7

In this problem set we explore the use of regexes (regular expressions) to examine patterns within our code. Regular expressions enable us to examine expressions in patterns, for a example that of an email address.

NUMB3RS

import re
import sys


def main():
    print(validate(input("IPv4 Address: ")))


def validate(ip):
    if matches := re.search(r"^(\d+)\.(\d+)\.(\d+)\.(\d+)$", ip):
        numbers = matches.groups()
        for n in numbers:
            if int(n) >=0 and int(n) <= 255:
                continue
            else:
                return False
    else:
        return False
    return True


if __name__ == "__main__":
    main()

from numb3rs import validate

def main():
    test_length()
    test_period()
    test_range()

def test_length():
    assert validate("1.2.3.4") == True
    assert validate("0.1.2.3") == True
    assert validate("1.2.3.4.5") == False

def test_period():
    assert validate("1.2.3.4.") == False
    assert validate(".1.2.3.4.") == False
    assert validate(".1.2.3.4") == False

def test_range():
    assert validate("256.257.258.259") == False
    assert validate("250.257.258.259") == False
    assert validate("-256.257.258.259") == False
    assert validate("-1.-2.-3.-4") == False
    assert validate("255.200.100.0") == True

Watch on YouTube

import re
import sys


def main():
    print(parse(input("HTML: ")))


def parse(s):
    if matches := re.search(r"^<iframe\s?(?:width=\"\d+\")?\s?(?:height=\"\d+\")?\ssrc=\"https?://(?:www\.)?youtube.com/embed/(\w+)+\"\s?(?:title=\"Youtube video player\")?\s?(?:frameborder=\"\d+\")?\s?(?:allow=\"(?:(?:(?:\w|-)+);?\s?)+\")?\s?(?:allowfullscreen)?></iframe>$", s, re.IGNORECASE):
        return f"https://youtu.be/{matches.group(1)}"



if __name__ == "__main__":
    main()

Working 9 to 5

import re
import sys


def main():
    print(convert(input("Hours: ")))


def convert(s):
    matches = re.search(r"^(1[0-2]|[0-9]):[0-5][0-9]\s(AM|PM)\sto\s(1[0-2]|[0-9]):[0-5][0-9]\s(AM|PM)$", s) or \
        re.search(r"^(1[0-2]|[0-9])\s(AM|PM)\sto\s(1[0-2]|[0-9])\s(AM|PM)$",s)
    if matches:
        if re.search(":", s):
            return process1(s)
        else:
            return process2(s)
    else:
        raise ValueError


def process1(s):
    new = []
    times = s.split(" to ")

    for time in times:
        if re.search("AM", time):
            time = time.replace(" AM","")
            hours, min = time.split(":")
            if int(hours) < 10:
                hours = "0" + hours
            elif int(hours) == 12:
                hours = "00"
            new.append(f"{hours}:{min}")
        else:
            time = time.replace(" PM","")
            hours, min = time.split(":")
            if int(hours) <= 10:
                hours = 12 + int(hours)
                hours = str(hours)
            elif int(hours) == 12:
                hours = "12"
            new.append(f"{hours}:{min}")

    return f"{new[0]} to {new[1]}"


def process2(s):
    new = []

    times = s.split(" to ")

    for time in times:
        if re.search("AM", time):
            time = time.replace(" AM", "")
            if int(time) < 10:
                time = "0" + time + ":00"
            elif int(time) == 12:
                time = "00:00"
            else:
                time = time + ":00"
            new.append(time)
        else:
            time = time.replace(" PM", "")
            if int(time) != 12:
                time = 12 + int(time)
                time = str(time) + ":00"
            else:
                time = "12:00"
            new.append(time)

    return f"{new[0]} to {new[1]}"


if __name__ == "__main__":
    main()

import pytest
from working import convert

def main():
    test_convert()
    test_omission()
    test_range()


def test_convert():
    assert convert("9 AM to 5 PM") == "09:00 to 17:00"
    assert convert("9:00 AM to 5:00 PM") == "09:00 to 17:00"
    assert convert("10 PM to 8 AM") == "22:00 to 08:00"


def test_omission():
    try:
        convert("9 AM 5 PM")
    except ValueError:
        pass
    else:
        assert False


def test_range():
    try:
        convert("13 AM to 19 PM")
    except ValueError:
        pass
    else:
        assert False


if __name__ == "__main__":
    main()

Regular, um, Expressions

import re
import sys


def main():
    print(count(input("Text: ")))


def count(s):
    matches = re.findall(r"\bum\b", s, re.IGNORECASE)
    return len(matches)


if __name__ == "__main__":
    main()

from um import count


def main():
    test_count()
    test_word_bound()
    test_case()


def test_count():
    assert count("um") == 1


def test_word_bound():
    assert count("yummy") == 0
    assert count("umm mum") == 0
    assert count("um mummy") == 1


def test_case():
    assert count("UM") == 1
    assert count("Um") == 1


if __name__ == "__main__":
    main()

Response Validation