Enigma 2 | Python Fiddle

alpha = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z']
def intro():
    output=[]
    global output
    phrase=input("Enter a phrase to work with (/ used for space): ")
    phrase=phrase.lower()
    global phrase
    s1=input("Enter setting number 1, x < 10: ")
    s2=input("Enter setting number 2, x < 10: ")
    s3=input("Enter setting number 3, x < 10: ")
    s4=input("Enter setting number 4, x < 10: ")
    s1=int(s1)*2
    s2=int(s3)+3*2
    s3=int(s2)+4
    s4=int(s4)+2
    global s1
    global s2
    global s3
    global s4
intro()
def encode():
    for c in phrase:
        if c == "/":
            output.append('/')
        elif c == " ":
            output.append('-')
        else:
            pos_c=alpha.index(str(c))
            pos_c = pos_c+int(s1)
            pos_c = pos_c+int(s2)
            pos_c = pos_c+int(s3)
            pos_c = pos_c-int(s4)
            output.append(alpha[pos_c].upper())
        output.append('')
    print (''.join(output))
    input("Press Enter To Continue...")
def decode():
    for c in phrase:
        if c == "/":
            output.append('/')
        elif c == " ":
            output.append('')
        else:
            pos_c=alpha.index(str(c))
            pos_c = pos_c-int(s1)
            pos_c = pos_c-int(s2)
            pos_c = pos_c-int(s3)
            pos_c = pos_c+int(s4)
            output.append(alpha[pos_c].upper())
        output.append(' ')
    print(''.join(output))
    input("Press Enter To Continue...")
def main_menu():
    main=input("Would you like to [encode] or [decode]?: ")
    if main == "encode":
        encode()
    elif main == "decode":
        decode()
    else:
        print("Sorry, that input was not an option!")
        main_menu()
main_menu()

Python Fiddle

Python Cloud IDE