Why am I getting TypeError: expected string or buffer?

Question

This is my tweets file

#!/usr/bin/env python3

    import os
    import sys

    from analyzer import Analyzer
    from termcolor import colored
    from helpers import get_user_timeline

    def main():

        # ensure proper usage
        if len(sys.argv)!=2 or sys.argv[1][0]!="@":
            sys.exit("Usage: ./tweets @userstweeter")

        # get tweets
        tweets = get_user_timeline(sys.argv[1][1:], 50)
        if tweets == None:
            sys.exit("Error")  
        print (tweets)

        # absolute paths to lists
        positives = os.path.join(sys.path[0], "positive-words.txt")
        negatives = os.path.join(sys.path[0], "negative-words.txt")

        # instantiate analyzer
        analyzer = Analyzer(positives, negatives)

        # analyze word
        score = analyzer.analyze(tweets)
        if score > 0.0:
            print(colored(":)", "green"))
        elif score < 0.0:
            print(colored(":(", "red"))
        else:
            print(colored(":|", "yellow"))

    if __name__ == "__main__":
        main()

This is my analyzer.py

import nltk
import string
import sys

from nltk.tokenize import TweetTokenizer

class Analyzer():
    """Implements sentiment analysis."""

    def __init__(self, positives, negatives):
        """Initialize Analyzer."""

        self.positives = set()
        with open("positive-words.txt") as file:
            for line in file:
                if line[0]!=" " and line[0]!=";":
                    self.positives.add(line.rstrip("\n"))

        self.negatives = set()
        with open("positive-words.txt") as file:
            for line in file:
                if not line.startswith(';') and not line.startswith(' '):
                    self.positives.add(line.rstrip("\n"))

    def analyze(self, text):
        """Analyze text for sentiment, returning its score."""

        tokenizer = nltk.tokenize.TweetTokenizer(preserve_case=False)
        tokens = tokenizer.tokenize(text)

        pos = 0
        neg = 0
        for tok in tokens:
            if tok in self.positives:
                pos += 1
            if tok in self.negatives:
                neg -= 1

        return pos + neg

This is the error.

Traceback (most recent call last):
      File "./tweets", line 39, in <module>
        main()
      File "./tweets", line 30, in main
        score = analyzer.analyze(tweets)
      File "/home/ubuntu/workspace/pset6/sentiments/analyzer.py", line 29, in analyze
        tokens = tokenizer.tokenize(text)
      File "/home/ubuntu/.local/lib/python3.4/site-packages/nltk/tokenize/casual.py", line 294, in tokenize
        text = _replace_html_entities(text)
      File "/home/ubuntu/.local/lib/python3.4/site-packages/nltk/tokenize/casual.py", line 258, in _replace_html_entities
        return ENT_RE.sub(_convert_entity, _str_to_unicode(text, encoding))
    TypeError: expected string or buffer

Answer 1

The problem is get_user_timeline because it returns a list of strings i.e you can't just pass it to the tokenize function. Instead you have to iterate over the strings and tokenize them seperatly.