pset 6

hello

Implement a program that prints out a simple greeting to the user, per the below.

$ python hello.py
What is your name?
David
hello, David

from cs50 import get_string

name = get_string("What is your name?\n")
print("hello,", name)

mario

Implement a program that prints out a double half-pyramid of a specified height, per the below.

$ ./mario
Height: 4
   #  #
  ##  ##
 ###  ###
####  ####

from cs50 import get_int

while True:
    height = get_int("Height: ")
    if height > 0 and height < 9:
        break

for i in range(height):
    for j in range(height - i - 1):
        print(" ", end="")
    for j in range(i + 1):
        print("#", end="")

    print("  ", end="")

    for j in range(i + 1):
        print("#", end="")
    print()

credit

Implement a program that determines whether a provided credit card number is valid according to Luhn’s algorithm.

$ python credit.py
Number: 378282246310005
AMEX

from cs50 import get_int

dig = 0


def main():
    num = get_int("Number: ")
    if (fraudCheck(num)):
        print(serviceDetect(num))
    else:
        print("INVALID")


def fraudCheck(num):
    mulsum = regsum = 0
    buf = False
    global dig
    while num > 0:
        if (buf == False):
            regsum += (num % 10)
            num = int(num / 10)
            buf = True
        else:
            k = 2 * (num % 10)
            if (k >= 10):
                mulsum += (k % 10)
                k = int(k / 10)
                mulsum += k
            else:
                mulsum += k
            num = int(num / 10)
            buf = False
        dig += 1

    if (mulsum + regsum) % 10:
        return False
    return True


def serviceDetect(num):
    global dig
    print(dig)
    if (dig == 13 and int(num / 10 ** 12) == 4):
        return "VISA"
    elif (dig == 16):
        if (int(num / 10 ** 15) == 4):
            return "VISA"
        elif (int(num / 10 ** 14) >= 51 and int(num / 10 ** 14) <= 55):
            return "MASTERCARD"
        else:
            return "INVALID"
    elif (dig == 15):
        if (int(num / 10 ** 13) == 34 or int(num / 10 ** 13) == 37):
            return "AMEX"
        else:
            return "INVALID"
    else:
        return "INVALID"


main()

readability

Implement a program that computes the approximate grade level needed to comprehend some text, per the below.

$ python readability.py
Text: Congratulations! Today is your day. You're off to Great Places! You're off and away!
Grade 3

from cs50 import get_string


def main():
    text = get_string("Text: ")
    letters = count_letters(text)
    words = count_words(text)
    sentences = count_sentences(text)
    L = (letters / words) * 100
    S = (sentences / words) * 100
    i = 0.0588 * L - 0.296 * S - 15.8
    index = round(i)

    if index < 1:
        print("Before Grade 1")
    elif index >= 16:
        print("Grade 16+")
    else:
        print(f"Grade {index}")


def count_letters(s):
    count = 0
    for c in s:
        if c.isalpha():
            count += 1

    return count


def count_words(s):
    count = 0
    for c in s:
        if c.isspace():
            count += 1

    return count + 1


def count_sentences(s):
    count = 0
    for c in s:
        if c == '.' or c == '!' or c == '?':
            count += 1

    return count


main()

dna

Implement a program that identifies a person based on their DNA Short Tandem Repeats (STRs), per the below.

database example:

name,AGAT,AATG,TATC
Alice,28,42,14
Bob,17,22,19
Charlie,36,18,25

$ python dna.py databases/large.csv sequences/5.txt
Lavender

Directorydatabases
- large.csv
- small.csv
Directorysequences
- *.txt
dna.py

import sys
import csv
import re

if len(sys.argv) != 3:
    print("Usage: python dna.py database.csv sequence.txt")
    sys.exit(1)

database = {}
with open(sys.argv[1], 'r') as csvfile:
    csvreader = csv.reader(csvfile)
    field = next(csvreader)
    field.remove(field[0])
    field = tuple(field)
    for row in csvreader:
        database[tuple(row[1:])] = row[0]

with open(sys.argv[2], 'r') as txtfile:
    sequence = txtfile.read()

count = {}
for value in field:
    # https://www.geeksforgeeks.org/python-maximum-consecutive-substring-occurrence/
    # Maximum Consecutive Substring  Occurrence
    # Using max() + re.findall()
    largest = max(re.findall('((?:' + re.escape(value) + ')*)', sequence), key=len)

    # can also be done like below(source: https://stackoverflow.com/a/61131908/9177454)
    # largest = max(re.findall(r'(?:' + value + ')+', sequence), key = len)
    count[value] = len(largest) // len(value)

result = [str(count[key]) for key in count]
result = tuple(result)

if result in database:
    print(database[result])
else:
    print("No match")