Count too high following where

[evandavey]

Code (data-forge 1.8.12):

const dataForge = require('data-forge');

const data = [100, 100, null, null];

const series = new dataForge.Series(data).where((val) => !isNaN(val));

console.log(series.toArray(), `count=${series.count()}`, `average=${series.average()}`);

Output:

[ 100, 100 ] count=4 average=50

Expected Output

[ 100, 100 ] count=2 average=100

What am I missing?

[ashleydavis]

Good catch!

It seems that nulls are being treated as zeros by count and average functions.

[ashleydavis]

So it looks like your filter is not removing the nulls.

Do it like this:

const series = new dataForge.Series(data).where((val) => val !== null);

Arguably functions like average should automatically remove undefined and null. I'll consider implementing that in the future.

[evandavey]

Shouldn't that mean series.toArray() should be [100, 100, null, null]?

[ashleydavis]

toArray filters out null and undefined values.

average and other mathematical functions should probably do this as well.

[ashleydavis]

This issue has been fixed.

All the DF maths functions (sum, average, std, invert, min, max) now either strip or ignore nulls and undefined.

This has been published in Data-Forge v1.8.17.