Can I make a code in python that ignores special characters such as commas, spaces, exclamation points, etc?

Question

I want to create a code that will return \"true\" (if I type in a palindrome regardless of case or if there are special characters in it), and \"false\" otherwise. The code I ha

Answer 1

You need to filter before testing then:

letters = [c.casefold() for c in my_str if c.isalpha()]

would pick out only the letters and lowercase them, after which you can test of those letters form a palindrome:

return letters == letters[::-1]

This works because str.isalpha() returns True only for letters.

Combined into your function:

def is_palindrome(my_str):
    letters = [c.casefold() for c in my_str if c.isalpha()]
    return letters == letters[::-1]

Demo:

>>> def is_palindrome(my_str):
...     letters = [c.casefold() for c in my_str if c.isalpha()]
...     return letters == letters[::-1]
... 
>>> is_palindrome("Rats live on no evil star")
True
>>> is_palindrome("Hello World!")
False
>>> is_palindrome("Madam, I'm Adam")
True

Answer 2

If you just want to exclude punctuation and spaces you can use str.translate:

from string import punctuation

d = {k: None for k in punctuation}
d[" "] = None

def is_palindrome(my_str):
    trans = str.maketrans(d)
    my_str = my_str.translate(trans).casefold()
    return my_str == my_str[::-1]

Answer 3

You may get just alphanumeric character in your string;

re.sub(r'[^a-zA-Z0-9]+', '', your_string).lower()

By the way this one works, if you ignores non-ASCII chars.

Answer 4

my_str = my_str.casefold()
my_str = ''.join(e for e in my_str if e.isalpha())

This should recreate my_str with only alphabetical characters, using .isalpha(). Then do the test on that. If you want to keep a record of original string, just stored the recreated version is a temporary string.