/// <summary> Get the time period spanned by tweets. </summary>
///
/// <param name="tweets">
/// list of tweets with distinct ids, not modified by this method.
/// </param>
///
/// <returns>
/// a minimum-length time interval that contains the timestamp of
/// every tweet in the list. If the list is empty, return a timespan
/// of size zero.
/// </returns>
///
public static Timespan GetTimespan(List <Tweet> tweets)
{
if (tweets.Count == 0)
{
DateTime fakeStart = DateTime.Parse("2016-02-17T10:00:00Z");
DateTime fakeEnd = DateTime.Parse("2016-02-17T10:00:00Z");
Timespan empty = new Timespan(fakeStart, fakeEnd);
return(empty);
}
else
{
DateTime current = tweets[0].timestamp;
DateTime latest = tweets[0].timestamp;
DateTime earliest = tweets[0].timestamp;
foreach (Tweet tweet in tweets)
{
current = tweet.timestamp;
int earlierOrNot = DateTime.Compare(current, earliest);
int laterOrNot = DateTime.Compare(current, latest);
if (earlierOrNot < 0)
{
earliest = current;
}
if (laterOrNot > 0)
{
latest = current;
}
}
Timespan span = new Timespan(earliest, latest);
return(span);
}
//throw new Exception("not implemented");
}
/// <summary>
/// Find tweets that were sent during a particular timespan.
/// </summary>
///
/// <param name="tweets">
/// a list of tweets with distinct ids, not modified by this method.
/// </param>
/// <param name="timespan">
/// timespan
/// </param>
/// <returns>
/// all and only the tweets in the list that were sent during the timespan,
/// in the same order as in the input list.
/// </returns>
public static List <Tweet> InTimespan(List <Tweet> tweets, Timespan timespan)
{
//throw new Exception("not implemented");
if ((tweets.Count == 0) | (timespan.duration == 0))
{
List <Tweet> empty = new List <Tweet>();
return(empty);
}
else
{
List <Tweet> ocurred = new List <Tweet>();
DateTime current;
DateTime latest = timespan.end;
DateTime earliest = timespan.start;
foreach (Tweet tweet in tweets)
{
current = tweet.timestamp;
int earlierOrNot = DateTime.Compare(current, earliest);
int laterOrNot = DateTime.Compare(current, latest);
if ((earlierOrNot >= 0) && (laterOrNot <= 0))
{
ocurred.Add(tweet);
}
}
return(ocurred);
}
}
public void TestGetTimespanEmptyTweets()
{
List <Tweet> list = new List <Tweet>();
double noTime = 0;
Timespan timespan = Extract.GetTimespan(list);
Assert.AreEqual(timespan.duration, noTime, "expected 0 size timespan");
}
public void TestGetTimespanTwoTweets()
{
List <Tweet> list = new List <Tweet>()
{
tweet1,
tweet2
};
Timespan timespan = Extract.GetTimespan(list);
Assert.AreEqual(d1, timespan.start, "expected start");
Assert.AreEqual(d2, timespan.end, "expected end");
}
/// <see cref="object.Equals">
public override bool Equals(object thatObject)
{
Timespan that = thatObject as Timespan;
if (that == null)
{
return(false);
}
return(_start.Equals(that._start) &&
_end.Equals(that._end));
}
public void TestGetTimespanDecendingTweets()
{
DateTime dt1 = DateTime.Parse("2016-02-17T10:00:06Z");
DateTime dt2 = DateTime.Parse("2016-02-17T10:00:03Z");
DateTime dt3 = DateTime.Parse("2016-02-17T10:00:00Z");
Tweet t1 = new Tweet(1, "alyssa", "is it @bbitdiddle who talks about rivest so much?", dt1);
Tweet t2 = new Tweet(2, "bbitdiddle", "@alyssa talks for minimum 30 minutes @Ellen #hype", dt2);
Tweet t3 = new Tweet(3, "bibimbop", "@alyssa talks for minimum 30 minutes @Ellen #NoHype", dt3);
List <Tweet> listt = new List <Tweet>()
{
t1, t2, t3
};
Timespan timespan = Extract.GetTimespan(listt);
double span = 6;
Assert.AreEqual(timespan.duration, span, "expected 6 sec timespan");
}
//
// Main method of the program. Fetches a sample of tweets and prints some
// facts about it.
//
public static void Main()
{
List <Tweet> tweets;
try
{
tweets = TweetReader.ReadTweetsFromWeb(SAMPLE_SERVER);
}
catch (Exception e)
{
throw new Exception("Cannot read tweets", e);
}
// display some characteristics about the tweets
Console.WriteLine("fetched " + tweets.Count + " tweets");
HashSet <string> mentionedUsers = Extract.GetMentionedUsers(tweets);
Console.WriteLine("covers " + mentionedUsers.Count + " Twitter users");
Timespan span = Extract.GetTimespan(tweets);
Console.WriteLine("ranging from " + span.start + " to " + span.end);
// infer the follows graph
Dictionary <string, HashSet <string> > followsGraph =
SocialNetwork.GuessFollowsGraph(tweets);
Console.WriteLine("follows graph has " + followsGraph.Count + " nodes");
// print the top-N influencers
int count = 10;
List <string> influencers = SocialNetwork.Influencers(followsGraph);
foreach (string username in
influencers.GetRange(0, Math.Min(count, influencers.Count)))
{
Console.WriteLine(username);
}
}
