Python如何将字符转换为字符串

Question

array = "qwertyuiopasdfghjklzxcvbnm"

m = len(array)
user_input= input("Enter plaintext: ")
a= int(input("choose a: "))
b= int(input("choose b: "))

encryption = ""
for n in array:

   if n in user_input :
    
    inin=array.find(n)
    result =array.index(user_input) * a+b
    enc= result % m
    encryption = encryption + array[enc]
    
    
    
    
   
 print("Encrypted message is :"+encryption)
    
    
   

as you can see from the code above my code worked fine but the only problem that I am facing is I need to encrypt the message as string like I want to use " hello world" not only a character "s" and its encrypted to " d" i want "hello word"

Answer 1

I tried to correct your code:

array = "qwertyuiopasdfghjklzxcvbnm"

m = len(array)
user_input= input("Enter plaintext: ")
a= int(input("choose a: "))
b= int(input("choose b: "))

encryption = ""
for char in user_input:
   if char in array :
    index = (array.find(char) * a + b) % m
    encryption += array[index]
   else:
    encryption += char

print("Encrypted message is :", encryption)

From what I understood, you are trying to encrypt your message by shifting the index using an affine function (and applying a modulo so it "loops" if the index is bigger than your alphabet size). Since your input can contain multiple times the same char, you need to iterate through the input and then check for the index of every char in your alphabet (array). Then you can apply your formula to the index and get the new char. I also added a code to add the unciphered char if it doesn't exist in your array. This will prevent you to lose informations when ciphering. eg: hello world will be ciphered in xirrm tmars instead of xirrmtmars which couldn't be unciphered to get the original.