How to replace letters with another letters to create a encryption code?-CodePudding

I've been told in a project to create an encryption code using python, by replacing all the letters in alphabets with other random letters using a dictionary (ASCII). And let the user type something, then show him the encrypted message.

I did this but apparently it didn't work out:

string = input("Write a sentence to encrypt: ")

print(string.replace("a", "j"))
print(string.replace("b", "f"))
print(string.replace("c", "n"))
print(string.replace("d", "t"))

print(string.replace)

When I tried this code and added more and more letters, it didn't work (example: I typed "abc" to test it and instead of giving me "jfn" in output, it gives me "jyn").

string = input("Write a sentence to encrypt: ")

string = string.replace("a", "j")
string = string.replace("b", "f")
string = string.replace("c", "n")
string = string.replace("d", "t")
string = string.replace("e", "g")
string = string.replace("f", "y")
string = string.replace("g", "i")

print(string)

Output:

Write a sentence to encrypt: abc
jyn

Process finished with exit code 0

CodePudding user response：

The str.replace function doesn't update the string in-place, it actually returns a copy. You need to keep that copy, otherwise you don't keep the modifications.

Your last print also prints the function, as opposed to the string.

Try something like

string = input("Write a sentence to encrypt: ")

string = string.replace("a", "j")
string = string.replace("b", "f")
string = string.replace("c", "n")
string = string.replace("d", "t")

print(string)

CodePudding user response：

You should take care of not replacing characters that have already been replaced.

Something like the following could work for you.

mapping = dict(zip('abc', 'xyz'))
string = 'abacabcd'

''.join(map(lambda char: mapping.get(char, char), string))