Text classification : Target 4294967295 is out of bounds

[LittleLittleCloud]

System Information (please complete the following information):

• ML.NET Version: 2.0

Describe the bug

Detailed info can be found in
#dotnet/machinelearning-modelbuilder#2369

[LittleLittleCloud]

It seems that if label's value is NaN or any values that not appear in ValueToKey term mapper, that label will be mapped to 0.

machinelearning/src/Microsoft.ML.Data/Transforms/ValueToKeyMappingTransformerImpl.cs

Line 720 in 9d798f1

public override ValueMapper<T, uint> GetKeyMapper()

So maybe a fix can be proccessing data and filter out the rows where label is null before training in text classification?

[michaelgsharp]

Yeah, the torch sharp model is 1 based. I don't know if they have an "unknown" value or not. If they do we need to map 0 to that correctly. If not we need to filter it out before we pass it.