ML.NET thows an error Column 'Time' has values of DateTime, which is not the same as earlier observed type of Single
I was trying to use ML.NET to do some simple linear regression test using a small dataset (760 items) but when I am calling Fit() to get a transformer it throws an eror "Column ‘Time’ has values of DateTime, which is not the same as earlier observed type of Single. "
as if the function confused the type of each column in the csv?
the code
public class PriceData { [ColumnName("Time")] [LoadColumn(0)] public DateTime Time; [ColumnName("ClosePrice")] [LoadColumn(1)] public float ClosePrice; } public class DemandPrediction { [ColumnName("Score")] public float ApproximationScore; } static string URL = "https://bittrex.com/Api/v2.0/pub/market/GetTicks?marketName=USD-BTC&tickInterval=day"; public static void Main(string[] args) { try { List<PriceData> priceData = new List<PriceData>(); DownloadData(URL,ref priceData); var context = new MLContext(); var data = context.Data.LoadFromTextFile<PriceData>("data.csv",hasHeader:false,separatorChar:','); var pipeline = context.Transforms.Concatenate(outputColumnName:"PriceData", nameof(PriceData.Time), nameof(PriceData.ClosePrice) ).AppendCacheCheckpoint(context); var trainerType = context.Regression.Trainers.OnlineGradientDescent(lossFunction: new TweedieLoss()); var fullPipeline = pipeline.Append(trainerType); var model = pipeline.Fit(data); var predictions = model.Transform(data); var metrics = context.Regression.Evaluate( data: predictions, labelColumnName: "ClosePrice", scoreColumnName: "Score"); var sample = new PriceData { Time =Convert.ToDateTime("7/6/2020 12:00:00 AM"), ClosePrice = 9273.18f }; // create a prediction engine var engine = context.Model.CreatePredictionEngine<PriceData, DemandPrediction>(model); // make the prediction var prediction = engine.Predict(sample); Console.ReadKey(); } catch (WebException e) { Console.WriteLine(e.Message); } }``` 
If you open the csv up in notepad, what do the Time values look like? Are they integer values? You may need to convert from Integer value to DateTime. See: How do I convert an Excel serial date number to a .NET DateTime?
