Smiple Question

[rickyplc]

This is a very sweet project!

I would like to know how can I convert the comparative value to a whole number (percentage 100), where 100 is the most positive, 50 is neutral and 0 is most negative?

This can also be out of 10.

[thisandagain]

The comparative score is simply: sum of each token / number of tokens. So for example let's take the following:

I love cats, but I am allergic to them.

That string results in the following:

{
    score: 1,
    comparative: 0.1111111111111111,
    tokens: [
        'i',
        'love',
        'cats',
        'but',
        'i',
        'am',
        'allergic',
        'to',
        'them'
    ],
    words: [
        'allergic',
        'love'
    ],
    positive: [
        'love'
    ],
    negative: [
        'allergic'
    ]
}

Each token has a range between 5 (positive) and -5 (negative). In this case, love has a value of 3, allergic has a value of -2, and the remaining tokens are neutral with a value of 0. Because the string has 9 tokens the resulting comparative score looks like:

(3 + -2) / 9 = 0.111111111

This approach leaves you with a mid-point of 0 and the upper and lower bounds are constrained to positive and negative 5 respectively (the same as each token! 😸). For example, let's imagine an incredibly "positive" string with 200 tokens and where each token has an AFINN score of 5. Our resulting comparative score would look like this:

(max positive score * number of tokens) / number of tokens
(5 * 200) / 200 = 5

So – to answer your question – you can scale and offset the comparative score (x) however you like using simple arithmetic. For example:

Scale from 0 to 100
(x + 5) * 10

[rickyplc]

Thank you very much! That was both fast and precisely detailed 👍.

And just so that I am clear. Taking the example you gave "I love cats, but I am allergic to them." would be:

Scale from 0 to 100
(x + max AFINN value) * 10
(0.1111111111111111+5)*10

And the value I am after would be 51.11%.

Where 5 would be the maximum AFINN value. Or is there a way to compute this value (max AFINN value) for all comparative scores?

[thisandagain]

(0.1111111111111111+5)*10

Yes. That's correct. The maximum AFINN value is always 5. To compute this you could do something like:

function scale (score) {
    return (score + 5) * 100;
}

var result = scale(sentiment('I like cats').comparative);

but I would recommend diving into JS to get a better sense of the possibilities:
http://jsforcats.com/
https://www.amazon.com/JavaScript-Good-Parts-Douglas-Crockford/dp/0596517742

[rickyplc]

Ahh yes, Mr Crockford (read that one already :)). Your awesome thanks! I will be able to build out the functionality, I'm not to shabby at Javascript.

And that function will work for all possibilities, including negatives, and neutral values?

[thisandagain]

And that function will work for all possibilities, including negatives, and neutral values?

Yup. You can give it a try yourself to see how it works in all scenarios.

[rickyplc]

Cool – thanks again!