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CS50 Problem Set 6
Here’s my answer for the CS50 Problem Set 6. Hope that will help you a bit.
Problem 1: Hello, Again
name = input("What is your name? ")
print(f"hello, {name}")hello.pyProbelm 2: Mario
while True:
try:
h = int(input("Height: "))
if 1 <= h <= 8:
break
else:
print("", end='')
except ValueError:
print("", end='')
for i in range(1, h+1):
for j in range(0, h-i):
print(" ", end='')
# j += 1
for k in range(0, i):
print("#", end='')
# k += 1
print(" ", end='')
for m in range(0, i):
print("#", end='')
# m += 1
print()mario.pyProblem 3: Credit
while True:
number = input("Number: ")
if number.isdigit() == True:
break
else:
number = input("Number: ")
reversed_number = number[::-1]
if len(number) == 15:
sum = 0
temp_sum_1 = 0
temp_sum_2 = 0
if number[:2] != "37" and number[:2] != "34":
print("INVALID")
else:
for i in range(1, 15, 2):
temp = int(reversed_number[i]) * 2
if temp > 9:
temp = temp // 10 + temp % 10
temp_sum_1 += temp
for i in range(0, 15, 2):
temp = int(reversed_number[i])
temp_sum_2 += temp
sum = temp_sum_1 + temp_sum_2
if sum % 10 == 0:
print("AMEX")
else:
print("INVALID")
elif len(number) == 13:
sum = 0
temp_sum_1 = 0
temp_sum_2 = 0
if number[:1] != "4":
print("INVALID")
else:
for i in range(1, 13, 2):
temp = int(reversed_number[i]) * 2
if temp > 9:
temp = temp // 10 + temp % 10
temp_sum_1 += temp
for i in range(0, 13, 2):
temp = int(reversed_number[i])
temp_sum_2 += temp
sum = temp_sum_1 + temp_sum_2
if sum % 10 == 0:
print("VISA")
else:
print("INVALID")
elif len(number) == 16:
sum = 0
temp_sum_1 = 0
temp_sum_2 = 0
if number[:1] != "4" and number[:2] != "51" and number[:2] != "52" and number[:2] != "53" and number[:2] != "54" and number[:2] != "55":
print("INVALID")
elif number[:1] == "4":
for i in range(1, 16, 2):
temp = int(reversed_number[i]) * 2
if temp > 9:
temp = temp // 10 + temp % 10
temp_sum_1 += temp
for i in range(0, 16, 2):
temp = int(reversed_number[i])
temp_sum_2 += temp
sum = temp_sum_1 + temp_sum_2
if sum % 10 == 0:
print("VISA")
else:
print("INVALID")
else:
for i in range(1, 16, 2):
temp = int(reversed_number[i]) * 2
if temp > 9:
temp = temp // 10 + temp % 10
temp_sum_1 += temp
for i in range(0, 16, 2):
temp = int(reversed_number[i])
temp_sum_2 += temp
sum = temp_sum_1 + temp_sum_2
if sum % 10 == 0:
print("MASTERCARD")
else:
print("INVALID")
else:
print("INVALID")credit.pyProblem 4: Readability
def words(text):
words = 1
for i in range(0, len(text)):
if text[i] == ' ':
words += 1
return words
def letters(text):
letters = 0
for i in range(0, len(text)):
if text[i].isalpha() == True:
letters += 1
return letters
def sentences(text):
sentences = 0
for i in range(0, len(text)):
if text[i] == '.' or text[i] == '!' or text[i] == '?':
sentences += 1
return sentences
text = input("Text: ")
index = round(0.0588 * letters(text) / words(text) * 100 -
0.296 * sentences(text) / words(text) * 100 - 15.8)
if index < 1:
print("Before Grade 1")
elif index >= 16:
print("Grade 16+")
else:
print(f"Grade {index}")readability.pyProblem 5: DNA
import csv
import sys
def main():
# TODO: Check for command-line usage
if len(sys.argv) != 3:
print("Missing command line arguments! ")
sys.exit()
# TODO: Read database file into a variable
database = []
with open(sys.argv[1], "r") as database_file:
reader = csv.DictReader(database_file)
for row in reader:
database.append(row)
# TODO: Read DNA sequence file into a variable
sequence = []
with open(sys.argv[2], "r") as sequence_file:
sequence = sequence_file.read()
# TODO: Find longest match of each STR in DNA sequence
str_count = {} # Initlize a list
for key in database[0].keys():
if key == "name":
continue
# When you insert a value but the key doesn't exist, python will create the key automatically and insert the value
str_count[key] = longest_match(sequence, key)
# TODO: Check database for matching profiles
for row in database:
match = True
# 遍历所有的key，并去除'name'
for key in row.keys():
if key == "name":
continue
# 当row[key]与str_count[key]不相等时，返回false，继续下一个key
if str_count[key] != int(row[key]):
match = False
break
if match:
print(row["name"])
return
print("No match")
def longest_match(sequence, subsequence):
"""Returns length of longest run of subsequence in sequence."""
# Initialize variables
longest_run = 0
subsequence_length = len(subsequence)
sequence_length = len(sequence)
# Check each character in sequence for most consecutive runs of subsequence
for i in range(sequence_length):
# Initialize count of consecutive runs
count = 0
# Check for a subsequence match in a "substring" (a subset of characters) within sequence
# If a match, move substring to next potential match in sequence
# Continue moving substring and checking for matches until out of consecutive matches
while True:
# Adjust substring start and end
start = i + count * subsequence_length
end = start + subsequence_length
# If there is a match in the substring
if sequence[start:end] == subsequence:
count += 1
# If there is no match in the substring
else:
break
# Update most consecutive matches found
longest_run = max(longest_run, count)
# After checking for runs at each character in sequence, return longest run found
return longest_run
main()dna.py