如何将我的代码转换为可正常使用的Caesar密码翻译器？

Question

I've been trying to work on this code of mine that takes a string of words, converts every letter into an ASCII code, adds a certain number (rotate_number), and then prints out the translated version of those numbers, all converted back into a string of random letters (but with the spaces and symbols remaining the same). For example, I want the string of "How are you today?" to rotate by a number of say +4, so that the final product says, "Lsa evi csy xshec?"

Here's the code I have so far, however when I run it, only one letter is rotated and printed out:

def encrypt_words(words, rotate_number):
    blank = ""
    for i in words:
        translate1 = ord(i) + rotate_number
        translated = chr(translate1)
        blank += translated
    print translated

encrypt_words("How are you today?", 3)

Also, I am sorry if my question has already been answered. I've been searching all across the web and this specific site, but nothing seems to work for me...

Answer 1

It looks like you want to be printing the string "blank", not translated as in your code. Try the following:

def encrypt_words(words, rotate_number):
    blank = ""
    for i in words:
        translate1 = ord(i) + rotate_number
        translated = chr(translate1)
        blank += translated
    print blank

Blank is the concatenation of each of the translated values. You should probably rename 'blank' as the name is misleading.

Answer 2

I would recommend first creating a rotate method

def rotate(alphabet,rotation):
    return alphabet[rotation:]+alphabet[:rotation]

#test it
print(rotate(string.ascii_lowercase,5))

now create a lookup table of the rotation

def create_lookup_table(rotation,*alphabets):
    if not alphabets:
       alphabets = [string.ascii_lowercase,string.ascii_uppercase]
    alphabet = "".join(alphabets)
    rotated = "".join(rotate(a,rotation) for a in alphabets)
    return dict(zip(alphabet,rotated))

# test it
create_lookup_table(5)
create_lookup_table(2,"abcdef","GHIJKLM")

now implementing ceasar cipher is trival because we have given ourselves the toolset to help us

def ceasar(msg_plain,rotation):
    lookup_table = create_lookup_table(rotation)
    return ''.join(lookup_table.get(char,char) for char in msg_plain)

# test it
ceasar("Hello World!",13) # 'Uryyb Jbeyq!'

Answer 3

You would want to do something like :

def encrypt_words(words, rotate_number):
    blank = ""
    for i in words:
        if i.isalpha():  # if part of alphabet shift with cipher
            translate1 = ord(i) + rotate_number
            translated = chr(translate1)
            blank += translated
        else:  # else leave as is
            blank += i
    print blank  # print entire word, not just last character
    # change blank variable to something that better describes function?