private SentimentAnalysisResults ScoreValence(List <double> sentiments, SentiText text)
{
if (sentiments.Count == 0)
{
return(new SentimentAnalysisResults()); //will return with all 0
}
var sum = sentiments.Sum();
var puncAmplifier = PunctuationEmphasis(text.Text);
sum += Math.Sign(sum) * puncAmplifier;
var compound = SentimentUtils.Normalize(sum);
var sifted = SiftSentimentScores(sentiments);
if (sifted.PosSum > Math.Abs(sifted.NegSum))
{
sifted.PosSum += puncAmplifier;
}
else if (sifted.PosSum < Math.Abs(sifted.NegSum))
{
sifted.NegSum -= puncAmplifier;
}
var total = sifted.PosSum + Math.Abs(sifted.NegSum) + sifted.NeuCount;
return(new SentimentAnalysisResults
{
Compound = Math.Round(compound, 4),
Positive = Math.Round(Math.Abs(sifted.PosSum / total), 3),
Negative = Math.Round(Math.Abs(sifted.NegSum / total), 3),
Neutral = Math.Round(Math.Abs(sifted.NeuCount / total), 3)
});
}
// Return metrics for positive, negative and neutral sentiment based on the input text.
public SentimentAnalysisResults PolarityScores(string input)
{
var sentiText = new SentiText(this, input);
var sentiments = AnalyseBoosters(sentiText);
sentiments = ButCheck(sentiText.WordsAndEmoticonsLowerCase, sentiments);
return(ScoreValence(sentiments, sentiText));
}
private List <double> AnalyseBoosters(SentiText sentiText)
{
var size = sentiText.WordsAndEmoticonsLowerCase.Count;
var sentiments = new List <double>();
for (var i = 0; i < size; i++)
{
var lowerCaseWord = sentiText.WordsAndEmoticonsLowerCase[i];
double valence = 0;
if (i < size - 1 && lowerCaseWord == "kind" && sentiText.WordsAndEmoticonsLowerCase[i + 1] == "of" ||
SentimentUtils.BoosterDict.ContainsKey(lowerCaseWord))
{
sentiments.Add(valence);
continue;
}
sentiments = SentimentValence(valence, sentiText,
sentiText.WordsAndEmoticons[i], lowerCaseWord,
i, sentiments);
}
return(sentiments);
}
private List <double> SentimentValence(double valence,
SentiText sentiText, string word,
string lowerCaseWord, int i,
List <double> sentiments)
{
if (!Lexicon.ContainsKey(lowerCaseWord))
{
sentiments.Add(valence);
return(sentiments);
}
var isCapDiff = sentiText.IsCapDifferential;
// adjust if shouting
valence = Lexicon[lowerCaseWord];
if (isCapDiff && word.IsUpper())
{
if (valence > 0)
{
valence += SentimentUtils.CIncr;
}
else
{
valence -= SentimentUtils.CIncr;
}
}
for (var startI = 0; startI < 3 && i > startI; startI++)
{
var offset = i - (startI + 1);
var lcWord = sentiText.WordsAndEmoticonsLowerCase[offset];
if (Lexicon.ContainsKey(lcWord))
{
continue;
}
var s = SentimentUtils.ScalarIncDec(lcWord,
sentiText.WordsAndEmoticons[offset], valence, isCapDiff);
if (startI == 1 && !s.Equals(0))
{
s = s * 0.95;
}
if (startI == 2 && !s.Equals(0))
{
s = s * 0.9;
}
valence = valence + s;
valence = NeverCheck(valence, sentiText.WordsAndEmoticonsLowerCase, startI, i);
if (startI == 2)
{
valence = IdiomsCheck(valence, sentiText.WordsAndEmoticonsLowerCase, i);
}
}
valence = LeastCheck(valence, sentiText.WordsAndEmoticonsLowerCase, i);
sentiments.Add(valence);
return(sentiments);
}