System.ArgumentOutOfRangeException: Schema mismatch for input column 'Label': expected KeyType, got Text

[suhaschitade]

Problem encountered on https://dotnet.microsoft.com/learn/machinelearning-ai/ml-dotnet-get-started-tutorial/code
Operating System: macos

Provide details about the problem you are experiencing. Include your operating system version, exact error message, code sample, and anything else that is relevant.

Unhandled Exception: System.ArgumentOutOfRangeException: Schema mismatch for input column 'Label': expected KeyType, got Text
Parameter name: inputSchema
at Microsoft.ML.Transforms.KeyToValueMappingEstimator.GetOutputSchema(SchemaShape inputSchema)
at Microsoft.ML.Data.EstimatorChain1.GetOutputSchema(SchemaShape inputSchema) at Microsoft.ML.Data.EstimatorChain1.Fit(IDataView input)
at myFirstML.Program.Main(String[] args) in /Users/suhaschitade/dotnetspace/ml/myFirstML/Program.cs:line 42

[CESARDELATORRE]

What version of ML.NET are you using?
The tutorial is still using ML.NET 0.11.

I think that’s a breaking change in 1.0.0-preview
We’ll update the tutorial to 1.0.0-preview pretty soon.

[CESARDELATORRE]

Closing this issue. The Getting Started tutorial has already been migrated to ML.NET 1.0.0-preview.
Please confirm it is working for you. Other than that, let's re-open this issue, ok?

Thanks! 👍

[suhaschitade]

Please open this issue, same behaviour observed after upgrading ML version, is this really production ready?

[CESARDELATORRE]

@suhaschitade - You must be doing any step wrong. I just went through the whole 'Getting Started' tutorial from a Mac and it works with no issues.

Note that the source-code is slightly different in ML.NET 1.0.0-preview compared to ML.NET 0.11.

Check it out in this screenshot:

Closing the issue. Feel free to open it if you still are having issues, ok?

Thanks,

[electroball09]

For posterity's sake, I had this issue because I had put MapKeyToValue() instead of MapValueToKey() when constructing the preprocessor pipeline.