Apr 27 2022 09:33 AM
Given a Microsoft.Data.Analysis DataFrame with two columns, what is the idiomatic way to take values from one column, manipulate them, then use the resulting value to fill the rows of the second column element-wise?
// Create a DateTime column. PrimitiveDataFrameColumn<DateTime> dateTimeCol = new("Dates", 0); // Fill it. dateTimeCol.Append(DateTime.Now + TimeSpan.FromDays(1)); dateTimeCol.Append(DateTime.Now + TimeSpan.FromDays(2)); dateTimeCol.Append(DateTime.Now + TimeSpan.FromDays(3)); // Create a Ticks column. PrimitiveDataFrameColumn<long> ticksCol = new("Ticks", dateTimeCol.Length); // Create a DataFrame of the above two columns. DataFrame df = new(); df.Columns.Add(dateTimeCol); df.Columns.Add(ticksCol);
At this point, what I want to do is df["Ticks"] = df["Dates"].Ticks. Of course, this doesn't work. I could do this:
for (int i = 0; i < df.Rows.Count; i++) { DateTime tempDate = (DateTime) df[i, df.Columns.IndexOf("Dates")]; df[i, df.Columns.IndexOf("Ticks")] = tempDate.Ticks; }
But... is there a better way?
May 03 2022 05:50 PM - edited May 03 2022 06:11 PM
Solution@chrisxfire not sure if this is what you were looking for, but you might be able to use the Apply function to take the values from one column, manipulate them, and save them to another column. Here's an example of that:
Alternatively, using the same data as above, you could also do the following which produces the same result:
I believe that the `Apply` method is implemented on PrimitiveDataFrameColumn, but not DataFrameColumn which is why you can't call it directly from `df["Numbers"]`
May 05 2022 09:37 AM
May 05 2022 10:49 AM
May 05 2022 11:24 AM
May 03 2022 05:50 PM - edited May 03 2022 06:11 PM
Solution@chrisxfire not sure if this is what you were looking for, but you might be able to use the Apply function to take the values from one column, manipulate them, and save them to another column. Here's an example of that:
Alternatively, using the same data as above, you could also do the following which produces the same result:
I believe that the `Apply` method is implemented on PrimitiveDataFrameColumn, but not DataFrameColumn which is why you can't call it directly from `df["Numbers"]`