Question

49

A somewhat painful triple-nested ternary operator

rated 0 times [ 55] [ 6] / answers: 1 / hits: 115148 / 12 Years ago, thu, may 10, 2012, 12:00:00

I went looking through Raphael.js's source code to find out how he converted RGB values to HSB. I found out the function he did it in and I was in the process of converting it to Python when I bumped into this nice triple-nested ternary operator:

H = (C == 0 ? null :

    V == r ? (g - b) / C :

    V == g ? (b - r) / C + 2 :

             (r - g) / C + 4

    );

It threw me for a loop because Python doesn't have the same kind of ternary operator that Javascript does. I spent a while looking over it and eventually hashed this somewhat saner code (using only if/else) out of it:

if (C == 0) {

    H = null;

} else {

    if(V == r) {

        H = (g - b) / C;

    } else {

        if(V == g) {

            H = (b - r) / C + 2;

        } else {

            H = (r - g) / C + 4;

        }

    }

}

Was my interpretation correct? I'm only asking this because if it isn't correct, I'm faced with a lot of debugging. So. Did I get it?

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cullenmaxl

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2 Years ago

answered 12 Years ago jenamackennac · Accepted Answer

I think you can have this to avoid the deep nesting:

var H



if(C == 0){

    H = null;

}

else if(V == r){

    H = (g - b) / C;

}

else if (V == g){

    H = (b - r) / C + 2;

}

else {

    H = (r - g) / C + 4;

}