Problem with python class

Question

Hi I am new to Python and as a part of my assignment I have written the following class

import nltk.stem.api

class BanglaStemmer(nltk.stem.api.StemmerI):

    suffixList = ['\xef\xbb\xbf\xe0\xa6\xbf\xe0\xa7\x9f\xe0\xa7\x87\xe0\xa6\x9b\xe0\xa6\xbf\xe0\xa6\xb2\xe0\xa6\xbe\xe0\xa6\xae\n', '\xe0\xa6\xbf\xe0\xa7\x9f\xe0\xa7\x87\xe0\xa6\x9b\xe0\xa6\xbf\xe0\xa6\xb2\xe0\xa7\x87\xe0\xa6\xa8\n', '\xe0\xa6\xbf\xe0\xa7\x9f\xe0\xa7\x87\xe0\xa6\x9b\xe0\xa6\xbf\xe0\xa6\xb2\xe0\xa7\x87\n', '\xe0\xa6\xbf\xe0\xa7\x9f\xe0\xa7\x87\xe0\xa6\x9b\xe0\xa6\xbf\xe0\xa6\xb2\xe0\xa6\xbf\n', '\xe0\xa6\xbf\xe0\xa7\x9f\xe0\xa7\x87\xe0\xa6\x9b\xe0\xa6\xbf\xe0\xa6\xb2\n', '\xe0\xa6\xbf\xe0\xa7\x9f\xe0\xa7\x87\xe0\xa6\x9b\xe0\xa7\x87\xe0\xa6\xa8\n', '\xe0\xa6\xbf\xe0\xa7\x9f\xe0\xa7\x87\xe0\xa6\x9b\xe0\xa6\xbf\xe0\xa6\xb8\n', '\xe0\xa6\xbf\xe0\xa7\x9f\xe0\xa7\x87\xe0\xa6\x9b\xe0\xa6\xbf\n', '\xe0\xa6\xbf\xe0\xa7\x9f\xe0\xa7\x87\xe0\xa6\x9b\xe0\xa7\x87\n', '\xe0\xa6\xbf\xe0\xa7\x9f\xe0\xa7\x87\xe0\xa6\x9b\n', '\xe0\xa6\xbf\xe0\xa7\x9f\xe0\xa7\x8b\n', '\xe0\xa7\x87\xe0\xa6\x9b\xe0\xa6\xbf\xe0\xa6\xb2\xe0\xa6\xbe\xe0\xa6\xae\n', '\xe0\xa7\x87\xe0\xa6\x9b\xe0\xa6\xbf\xe0\xa6\xb2\xe0\xa7\x87\xe0\xa6\xa8\n', '\xe0\xa7\x87\xe0\xa6\x9b\xe0\xa6\xbf\xe0\xa6\xb2\xe0\xa7\x87\n', '\xe0\xa7\x87\xe0\xa6\x9b\xe0\xa6\xbf\xe0\xa6\xb2\xe0\xa6\xbf\n', '\xe0\xa7\x87\xe0\xa6\x9b\xe0\xa6\xbf\xe0\xa6\xb2\n', '\xe0\xa7\x87\xe0\xa6\x9b\xe0\xa7\x87\xe0\xa6\xa8\n', '\xe0\xa7\x87\xe0\xa6\x9b\xe0\xa6\xbf\xe0\xa6\xb8\n', '\xe0\xa7\x87\xe0\xa6\x9b\xe0\xa6\xbf\n', '\xe0\xa7\x87\xe0\xa6\x9b\xe0\xa7\x87\n', '\xe0\xa7\x87\xe0\xa6\x9b\n', '\xe0\xa6\xa4\xe0\xa7\x87\n', '\xe0\xa6\x9a\xe0\xa7\x8d\xe0\xa6\x9b\xe0\xa6\xbf\xe0\xa6\xb2\xe0\xa6\xbe\xe0\xa6\xae\n', '\xe0\xa6\x9a\xe0\xa7\x8d\xe0\xa6\x9b\xe0\xa6\xbf\xe0\xa6\xb2\xe0\xa7\x87\xe0\xa6\xa8\n', '\xe0\xa6\x9a\xe0\xa7\x8d\xe0\xa6\x9b\xe0\xa6\xbf\xe0\xa6\xb2\xe0\xa7\x87\n', '\xe0\xa6\x9a\xe0\xa7\x8d\xe0\xa6\x9b\xe0\xa6\xbf\xe0\xa6\xb2\xe0\xa6\xbf\n', '\xe0\xa6\x9a\xe0\xa7\x8d\xe0\xa6\x9b\xe0\xa6\xbf\xe0\xa6\xb2\n', '\xe0\xa6\x9a\xe0\xa7\x8d\xe0\xa6\x9b\xe0\xa6\xbf\xe0\xa6\xb8\n', '\xe0\xa6\x9a\xe0\xa7\x8d\xe0\xa6\x9b\xe0\xa6\xbf\n', '\xe0\xa6\x9a\xe0\xa7\x8d\xe0\xa6\x9b\xe0\xa7\x87\xe0\xa6\xa8\n', '\xe0\xa6\x9a\xe0\xa7\x8d\xe0\xa6\x9b\xe0\xa7\x87\n', '\xe0\xa6\x9a\xe0\xa7\x8d\xe0\xa6\x9b\n', '\xe0\xa6\x9b\xe0\xa6\xbf\xe0\xa6\xb2\xe0\xa6\xbe\xe0\xa6\xae\n', '\xe0\xa6\x9b\xe0\xa6\xbf\xe0\xa6\xb2\xe0\xa7\x87\xe0\xa6\xa8\n', '\xe0\xa6\x9b\xe0\xa6\xbf\xe0\xa6\xb2\xe0\xa7\x87\n', '\xe0\xa6\x9b\xe0\xa6\xbf\xe0\xa6\xb2\xe0\xa6\xbf\n', '\xe0\xa6\x9b\xe0\xa6\xbf\xe0\xa6\xb2\n', '\xe0\xa6\x9b\xe0\xa6\xbf\xe0\xa6\xb8\n', '\xe0\xa6\x9b\xe0\xa6\xbf\n', '\xe0\xa6\x9b\xe0\xa7\x87\xe0\xa6\xa8\n', '\xe0\xa6\x9b\n', '\xe0\xa6\xa4\xe0\xa6\xbf\xe0\xa6\xb8\n', '\xe0\xa6\xa4\xe0\xa6\xbe\xe0\xa6\xae\n', '\xe0\xa6\xb2\xe0\xa6\xbe\xe0\xa6\xae\n', '\xe0\xa6\xb2\xe0\xa7\x87\xe0\xa6\xa8\n', '\xe0\xa6\xa4\xe0\xa7\x87\xe0\xa6\xa8\n', '\xe0\xa6\xac\xe0\xa7\x87\xe0\xa6\xa8\n', '\xe0\xa7\x87\xe0\xa6\xa8\n', '\xe0\xa6\xbf\xe0\xa6\xb8\n', '\xe0\xa7\x81\xe0\xa6\xa8\n', '\xe0\xa7\x81\xe0\xa6\x95\n', '\xe0\xa6\xb2\xe0\xa7\x87\n', '\xe0\xa6\xac\xe0\xa7\x87\n', '\xe0\xa6\xb2\xe0\xa6\xbf\n', '\xe0\xa6\xac\xe0\xa6\xbf\n', '\xe0\xa6\xa4\xe0\xa6\xbf\n', '\xe0\xa6\xb2\n', '\xe0\xa6\xa4\n', '\xe0\xa7\x8b\n', '\xe0\xa6\xbf\n', '\xe0\xa7\x87\n', '\xe0\xa7\x8d\n', '\xe0\xa6\x87\n', '\xe0\xa6\xac\n', '\xe0\xa6\xb8\n', '\xe0\xa6\xa8\n', '\xe0\xa6\x95\n', '\xe0\xa6\x93\n', '\xe0\xa7\x9f\n']

    def stem(self,token):
        for suffix in suffixList:
            if token.endswith(suffix):
                return token[:-len(suffix)]

        return token

The problem is that when I try to compile run it by creating an instance and calling the stem() function with a parameter , it says that the suffixList is not defined. Couldn't figure out what's the problem. Is there a different way in which the class variables have to be declared ? please help

Answer 1

You can use BanglaStemmer.suffixList or self.suffixList to access the variable. Plain suffixList would only work on a local (defined in the function) or a global (defined in the module) variable.

Answer 2

for suffix in suffixList:

should be

for suffix in self.suffixList:

Unlike a lot of OOP languages, Python requires you to qualify class members inside the class methods.

Answer 3

In Python, unlike most other languages, you always have to explicitely reference the instance of which you want to access a member (or "attribute" in Python). This instance is always passed as the first parameter to your methods; this is the reason why this first parameter is called self by convention.

suffixList in your case is a class attribute, i.e. it is shared by all instances of the class (unless redefined). So you access it with self.suffixList.