Remove index from Deedle Frame

Question

Suppose a dataframe is loaded like so:

let fr = Frame.ReadCsv("somedata.txt", hasHeaders=true, separators="\t") 
             |> Frame.indexRowsDate "Datetime"

The output of which looks something like this:

                        Open     High     Low      Close    
5/14/2015 7:02:00 AM -> 21.00000 21.01000 21.00000 21.01000 
5/14/2015 7:03:00 AM -> 22.01000 22.01000 22.93000 22.9500  

How do you transform the dataframe into the following:

     Datetime             Open     High     Low      Close    
0 -> 5/14/2015 7:02:00 AM 21.00000 21.01000 21.00000 21.01000 
1 -> 5/14/2015 7:03:00 AM 22.01000 22.01000 22.93000 22.9500  

Basically, how are indexes removed from a deedle dataframe and turned into a column of the dataframe.

Answer 1

Using the F#-friendly Deedle API, you can use addCol to add keys as a new column and then you can use indexRowsOrdinarilly to replace the original keys with plain numerical index:

df 
|> Frame.addCol "Keys" (df |> Frame.mapRows (fun k _ -> k))
|> Frame.indexRowsOrdinally

Alternatively, the first could also be done imperatively, which is a bit shorter:

f.AddColumn("Keys", f.RowKeys)
f |> Frame.indexRowsOrdinally