pset6 caesar in python

Question

I'm currently working in rewriting caesar into python, and I'm making good progress but I keep running into an error, after I enter the plaintext, it says

Traceback (most recent call last):
File "caesar.py", line 24, in <module>
main()
File "caesar.py", line 14, in main
if pt[i] + (k % 26) > 64 and pt[i] + (k % 26) < 91:
TypeError: not all arguments converted during string formatting

and I'm not sure how to fix the error. My code is: import cs50 import sys

def main():
    k = sys.argv[1]
    c = len(sys.argv)
    if c == 2:
        #print(k,c)
        sys.stdout.write("Plaintext: ")
        pt = cs50.get_string()
        ptl = range(0, len(pt))

        for i in ptl:
            if pt[i] + (k % 26) > 64 and pt[i] + (k % 26) < 91:
                sys.stdout.write(pt[i] + k % 26)


    else:
        return 1



if __name__ == "__main__":
    main()

Answer 1

In Python, characters are not integers. Use ord and chr to convert them.