invalid syntax in returning a list in python

Question

def rotate_word(word,number):
    new_word_number=[]
    new_word=[]
    for letter in word:
        new_word_number.append(ord(letter)+number)
        new_word.append(chr(new_word_number))
    return new_word   
                        
        
rotate_word('xyz',2)

This code is showing error TypeError: an integer is required (got type list)

Answer 1

No idea what you're trying to achieve, but here's a code that will work:

def rotate_word(word, number):
    new_word = []
    for letter in word:
        new_word.append(chr(ord(letter) + number))
    return ''.join(new_word)


print(rotate_word('xyz', 2))

Will print z{|

Note that you don't need two intermediary lists. Also, using ''.join(your_list) will allow to consolidate the resulting list into a string so your function returns the same type it's given.

Btw, if your initial goal was to achieve character rotation like rot13 (in your case rot2), you could use a smarter function that also only deals with alphabet characters to make the output portable (only printable characters):

def rotX(string: str, shift: int = 13):
    """
    RotX for only A-Z and a-z characters
    """
    try:
        return ''.join(
            [chr(ord(n) + (shift if 'Z' < n < 'n' or n < 'N' else -shift)) if ('a' <= n <= 'z' or 'A' <= n <= 'Z') else n for
             n in
             string])
    except TypeError:
        return None

result = rotX('xyz', 2)
reverse_result = rotX(result, -2)
print(result)
print(reverse_result)