CODEWITHSUNDEEP
pythonpython-3.x
prossellob
prossellob

Reputation: 779

How to recognise non letter from a string

Hi all :) I'm building a script to code text with a simple text rotation(ROT). The script works well, but I'm having a problem, it also rotates all symbols like [spaces,!,?,.] I'm working with ascii table to do it, what can i do to avoid rotating that type of characters?

def rot13(input,key): #Function to code a text with caeser chyper.
    if key > 25:
        key = 25
    elif key < 2:
        key = 2
    finaltext = ''
    for letter in input:
        num = ord(letter)
        if (num + key) > 122: #If the final number is greater than 122..
            x = (num + key) - 122
            finaltext += chr(x + ord('a') - 1)
        elif((num + key <= 122)):
            finaltext += chr(num + key)
    print(finaltext)

Upvotes: 1

Views: 75

Answers (2)

LoicM
LoicM

Reputation: 2203

before "rotating" your character, add a check to see whether or not it is alphanumeric:

if letter.isalpha():
    # Do your thing
else:
    finaltext += letter

Upvotes: 3

Szabolcs
Szabolcs

Reputation: 4086

Try this:

>>> import string
>>> letter = 'a'
>>> letter in string.letters
True
>>> letter = '.'
>>> letter in string.letters
False

Upvotes: 1

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