Sentiment analysis function (not using Classify)

Question

I am looking to create a function that will take a text and parameter strings "neg","pos", and "sum" and calculate a sentiment value for the text. I want to use ReplaceAll and/or "If' for this. I have two lists, one with negative (negativeWords) and one with positive words (positiveWords), and I want the function to assign the value of +1 to words in the text that are also in the positive words list, -1 to words in the text that are also in the negative words list, and 0 for words that are in neither list, and then calculate the sum of those numbers.

This is what I have so far but I am stumped :/

ToLowerCase@TextWords@text_ /. {negativeWords -> -1, positiveWords -> 1, ! negativeWords && ! positiveWords -> 0}

Answer 1

An Association together with Lookup and the default value 0 might do and should be reasonably efficient.

negativeWords = {"A", "B"};
positiveWords = {"a", "b"};

s = "A a b C, B a b A? A B b a c!";

a = Merge[{AssociationThread[positiveWords, 1], AssociationThread[negativeWords, -1]}, First]

Lookup[a, TextWords[s], 0]

{-1, 1, 1, 0, -1, 1, 1, -1, -1, -1, 1, 1, 0}