Python 3.5.2如何縮短這段代碼？

Question

我做了一些代碼，基本上用一個字母代替另一個字母，但問題是它需要很多代碼。

請告訴我如何縮短它。有沒有一種方法，我可以喜歡使用變量，而不需要寫很多行？

def begin(): 
    lock = input("Enter the passcode") 
    if lock == 'password': 
     start() 
    else: 
     print("Wrong passcode") 
     begin() 

def start(): 
    print("Put in each letter one by one") 
    print("Your message should be a 5 letter word") 
    letter1 = input("") 
    letter2 = input("") 
    letter3 = input("") 
    letter4 = input("") 
    letter5 = input("") 
#letter 1 
    if letter1 == 'f': 
     letter1 = 'a' 
    elif letter1 == 'g': 
     letter1 = 'b' 
    elif letter1 == 'h': 
     letter1 = 'c' 
    elif letter1 == 'i': 
     letter1 = 'd' 
    elif letter1 == 'j': 
     letter1 = 'e' 
    elif letter1 == 'k': 
     letter1 = 'f' 
    elif letter1 == 'l': 
     letter1 = 'g' 
    elif letter1 == 'm': 
     letter1 = 'h' 
    elif letter1 == 'n': 
     letter1 = 'i' 
    elif letter1 == 'o': 
     letter1 = 'j' 
    elif letter1 == 'p': 
     letter1 = 'k' 
    elif letter1 == 'q': 
     letter1 = 'l' 
    elif letter1 == 'r': 
     letter1 = 'm' 
    elif letter1 == 's': 
     letter1 = 'n' 
    elif letter1 == 't': 
     letter1 = 'o' 
    elif letter1 == 'u': 
     letter1 = 'p' 
    elif letter1 == 'v': 
     letter1 = 'q' 
    elif letter1 == 'w': 
     letter1 = 'r' 
    elif letter1 == 'x': 
     letter1 = 's' 
    elif letter1 == 'y': 
     letter1 = 't' 
    elif letter1 == 'z': 
     letter1 = 'u' 
    elif letter1 == 'a': 
     letter1 = 'v' 
    elif letter1 == 'b': 
     letter1 = 'w' 
    elif letter1 == 'c': 
     letter1 = 'x' 
    elif letter1 == 'd': 
     letter1 = 'y' 
    elif letter1 == 'e': 
     letter1 = 'z' 
#letter 2 
    if letter2 == 'f': 
     letter2 = 'a' 
    elif letter2 == 'g': 
     letter2 = 'b' 
    elif letter2 == 'h': 
     letter2 = 'c' 
    elif letter2 == 'i': 
     letter2 = 'd' 
    elif letter2 == 'j': 
     letter2 = 'e' 
    elif letter2 == 'k': 
     letter2 = 'f' 
    elif letter2 == 'l': 
     letter2 = 'g' 
    elif letter2 == 'm': 
     letter2 = 'h' 
    elif letter2 == 'n': 
     letter2 = 'i' 
    elif letter2 == 'o': 
     letter2 = 'j' 
    elif letter2 == 'p': 
     letter2 = 'k' 
    elif letter2 == 'q': 
     letter2 = 'l' 
    elif letter2 == 'r': 
     letter2 = 'm' 
    elif letter2 == 's': 
     letter2 = 'n' 
    elif letter2 == 't': 
     letter2 = 'o' 
    elif letter2 == 'u': 
     letter2 = 'p' 
    elif letter2 == 'v': 
     letter2 = 'q' 
    elif letter2 == 'w': 
     letter2 = 'r' 
    elif letter2 == 'x': 
     letter2 = 's' 
    elif letter2 == 'y': 
     letter2 = 't' 
    elif letter2 == 'z': 
     letter2 = 'u' 
    elif letter2 == 'a': 
     letter2 = 'v' 
    elif letter2 == 'b': 
     letter2 = 'w' 
    elif letter2 == 'c': 
     letter2 = 'x' 
    elif letter2 == 'd': 
     letter2 = 'y' 
    elif letter2 == 'e': 
     letter2 = 'z' 
#letter 3 
    if letter3 == 'f': 
     letter3 = 'a' 
    elif letter3 == 'g': 
     letter3 = 'b' 
    elif letter3 == 'h': 
     letter3 = 'c' 
    elif letter3 == 'i': 
     letter3 = 'd' 
    elif letter3 == 'j': 
     letter3 = 'e' 
    elif letter3 == 'k': 
     letter3 = 'f' 
    elif letter3 == 'l': 
     letter3 = 'g' 
    elif letter3 == 'm': 
     letter3 = 'h' 
    elif letter3 == 'n': 
     letter3 = 'i' 
    elif letter3 == 'o': 
     letter3 = 'j' 
    elif letter3 == 'p': 
     letter3 = 'k' 
    elif letter3 == 'q': 
     letter3 = 'l' 
    elif letter3 == 'r': 
     letter3 = 'm' 
    elif letter3 == 's': 
     letter3 = 'n' 
    elif letter3 == 't': 
     letter3 = 'o' 
    elif letter3 == 'u': 
     letter3 = 'p' 
    elif letter3 == 'v': 
     letter3 = 'q' 
    elif letter3 == 'w': 
     letter3 = 'r' 
    elif letter3 == 'x': 
     letter3 = 's' 
    elif letter3 == 'y': 
     letter3 = 't' 
    elif letter3 == 'z': 
     letter3 = 'u' 
    elif letter3 == 'a': 
     letter3 = 'v' 
    elif letter3 == 'b': 
     letter3 = 'w' 
    elif letter3 == 'c': 
     letter3 = 'x' 
    elif letter3 == 'd': 
     letter3 = 'y' 
    elif letter3 == 'e': 
     letter3 = 'z' 
#letter 4 
    if letter4 == 'f': 
     letter4 = 'a' 
    elif letter4 == 'g': 
     letter4 = 'b' 
    elif letter4 == 'h': 
     letter4 = 'c' 
    elif letter4 == 'i': 
     letter4 = 'd' 
    elif letter4 == 'j': 
     letter4 = 'e' 
    elif letter4 == 'k': 
     letter4 = 'f' 
    elif letter4 == 'l': 
     letter4 = 'g' 
    elif letter4 == 'm': 
     letter4 = 'h' 
    elif letter4 == 'n': 
     letter4 = 'i' 
    elif letter4 == 'o': 
     letter4 = 'j' 
    elif letter4 == 'p': 
     letter4 = 'k' 
    elif letter4 == 'q': 
     letter4 = 'l' 
    elif letter4 == 'r': 
     letter4 = 'm' 
    elif letter4 == 's': 
     letter4 = 'n' 
    elif letter4 == 't': 
     letter4 = 'o' 
    elif letter4 == 'u': 
     letter4 = 'p' 
    elif letter4 == 'v': 
     letter4 = 'q' 
    elif letter4 == 'w': 
     letter4 = 'r' 
    elif letter4 == 'x': 
     letter4 = 's' 
    elif letter4 == 'y': 
     letter4 = 't' 
    elif letter4 == 'z': 
     letter4 = 'u' 
    elif letter4 == 'a': 
     letter4 = 'v' 
    elif letter4 == 'b': 
     letter4 = 'w' 
    elif letter4 == 'c': 
     letter4 = 'x' 
    elif letter4 == 'd': 
     letter4 = 'y' 
    elif letter4 == 'e': 
     letter4 = 'z' 
#letter 5 
    if letter5 == 'f': 
     letter5 = 'a' 
    elif letter5 == 'g': 
     letter5 = 'b' 
    elif letter5 == 'h': 
     letter5 = 'c' 
    elif letter5 == 'i': 
     letter5 = 'd' 
    elif letter5 == 'j': 
     letter5 = 'e' 
    elif letter5 == 'k': 
     letter5 = 'f' 
    elif letter5 == 'l': 
     letter5 = 'g' 
    elif letter5 == 'm': 
     letter5 = 'h' 
    elif letter5 == 'n': 
     letter5 = 'i' 
    elif letter5 == 'o': 
     letter5 = 'j' 
    elif letter5 == 'p': 
     letter5 = 'k' 
    elif letter5 == 'q': 
     letter5 = 'l' 
    elif letter5 == 'r': 
     letter5 = 'm' 
    elif letter5 == 's': 
     letter5 = 'n' 
    elif letter5 == 't': 
     letter5 = 'o' 
    elif letter5 == 'u': 
     letter5 = 'p' 
    elif letter5 == 'v': 
     letter5 = 'q' 
    elif letter5 == 'w': 
     letter5 = 'r' 
    elif letter5 == 'x': 
     letter5 = 's' 
    elif letter5 == 'y': 
     letter5 = 't' 
    elif letter5 == 'z': 
     letter5 = 'u' 
    elif letter5 == 'a': 
     letter5 = 'v' 
    elif letter5 == 'b': 
     letter5 = 'w' 
    elif letter5 == 'c': 
     letter5 = 'x' 
    elif letter5 == 'd': 
     letter5 = 'y' 
    elif letter5 == 'e': 
     letter5 = 'z' 



    print("Your encypted message is:") 
    print(letter1 + letter2 + letter3 + letter4 + letter5) 
    QUIT = input("Press enter to quit") 
    quit 

begin() 

Answer 1

我會建議建立一個字典，從letter1映射到letter2喜歡與你的if語句。

letterMapping = {'f':'a','g':'b'}等一個，當你收到你的輸入只是做：

letter1 = input("") 
letterMapping[letter1] 

所以如果letter1是f它會返回a。

Answer 2

使用str.maketrans()創建翻譯表，並使用str.translate()來翻譯。使用string.ascii_lowercase而不是拼出你的字母。使用string.ascii_letters來處理大寫和小寫字母，這可能是一個不錯的改進。

>>> import string 
>>> letters = string.ascii_lowercase 
>>> table = str.maketrans(letters[5:]+letters[:5], letters) 
>>> str.translate('crown', table) 
'xmjri' 

或者創建一個字典用作翻譯表。使用默認值dict.get()以允許字符在未指定映射時通過未翻譯。

>>> import string 
>>> letters = string.ascii_lowercase 
>>> d = dict(zip(letters[5:]+letters[:5], letters)) 
>>> ''.join(d.get(c, c) for c in 'crown') 
'xmjri' 

Answer 3

嗨，爲什麼不嘗試使用while循環和數組。如果代碼的工作，但你會得到的想法

def start(): 
letters = array(); 
x = 0; 
while(x != 5): 
    print("Enter 1 letter"); 
    letters[x] = input(""); 
    x = x +1; 
while(x != 5): 
    if (letters[x] == 'f'): 
     letters[x] = 'a' 
    elif(letters[x] == 'g'): 
     letters[x] = 'b' 
    elif ((letters[x] == 'h'): 
     letters[x]= 'c' 
    elif (letters[x] == 'i'): 
     letters[x] = 'd' 
    elif (letters[x] == 'j'): 
     letters[x] = 'e' 
    elif (letters[x] == 'k'): 
     letters[x] = 'f' 
    elif (letters[x] == 'l'): 
     letters[x] = 'g' 
    elif (letters[x] == 'm'): 
     letters[x] = 'h' 
    elif (letters[x] == 'n'): 
     letters[x] = 'i' 
    elif (letters[x] == 'o'): 
     letters[x] = 'j' ; 
    elif (letters[x] == 'p'): 
     letters[x] = 'k' 
    elif (letters[x] == 'q'): 
     letters[x] = 'l' 
    elif (letters[x] == 'r'): 
     letters[x] = 'm' 
    elif (letters[x] == 's'): 
     letters[x] = 'n' 
    elif (letters[x] == 't'): 
     letters[x] = 'o' 
    elif (letters[x] == 'u'): 
     letters[x] = 'p' 
    elif (letters[x] == 'v'): 
     letters[x] = 'q' 
    elif (letters[x] == 'w'): 
     letters[x] = 'r' 
    elif (letters[x] == 'x'): 
     letters[x] = 's' 
    elif (letters[x] == 'y'): 
     letters[x] = 't' 
    elif (letters[x] == 'z'): 
     letters[x] = 'u' 
    elif (letters[x] == 'a'): 
     letters[x] = 'v' } 
    elif (letters[x] == 'b'): 
     letters[x] = 'w' 
    elif (letters[x] == 'c'): 
     letters[x] = 'x' 
    elif (letters[x] == 'd'): 
     letters[x] = 'y' 
    elif (letters[x] == 'e'): 
     letters[x] = 'z' 

    x = x + 1; 


print("Your encypted message is:") 
print(letters[0] + letters[1] + letters[2] + letters[3] + letters[4]) 
QUIT = input("Press enter to quit") 
quit