Python Twitter JSON parsing

"""
Simple Python example showing how to parse JSON-formatted Twitter messages+metadata
(i.e. data produced by the Twitter status tracking API)

This script simply creates Python lists containing the messages, locations and timezones
of all tweets in a single JSON file.

Author: Geert Barentsen - 4 April (#dotastro)
"""

import sys
import simplejson
import difflib

# Input argument is the filename of the JSON ascii file from the Twitter API
filename = sys.argv[1]

tweets_text = [] # We will store the text of every tweet in this list
tweets_location = [] # Location of every tweet (free text field - not always accurate or given)
tweets_timezone = [] # Timezone name of every tweet

# Loop over all lines
f = file(filename, "r")
lines = f.readlines()
for line in lines:
    try:
        tweet = simplejson.loads(line)

        # Ignore retweets!
        if tweet.has_key("retweeted_status") or not tweet.has_key("text"):
            continue

        # Fetch text from tweet
        text = tweet["text"].lower()

        # Ignore 'manual' retweets, i.e. messages starting with RT
        if text.find("rt ") > -1:
            continue

        tweets_text.append( text )
        tweets_location.append( tweet['user']['location'] )
        tweets_timezone.append( tweet['user']['time_zone'] )

    except ValueError:
        pass


# Show result
print tweets_text
print tweets_location
print tweets_timezone