CSV Type Provider cannot find column in F# interactive

Question

So let's say I have a CSV file with a header containing columns Population and Profit, and I'd like to work with it in F# interactive. I have the following code:

#r "../packages/FSharp.Data.1.1.10/lib/net40/FSharp.Data.dll"

open FSharp.Data

// load csv header
let cities = new CsvProvider<"cities.csv">()

// how to reach data
let firstRow = cities.Data |> Seq.head
let firstPopulation = firstRow.Population
let firstProfit = firstRow.Profit

I get an error from F# interactive:

error FS0039: The field, constructor or member 'Population' is not defined

This seems confusing to me, because intellisense in VS has no problem picking up this column from my data via a CSV type provider.

Also, I tried creating a program with the same type provider and it all works just fine. Like this:

open FSharp.Data

[<EntryPoint>]
let main argv = 
    use file = System.IO.File.CreateText("result.txt")
    let csv = new CsvProvider<"cities.csv">()
    for record in csv.Data do
        fprintfn file "%A" record.Population
    0

Am I missing something? Thanks for any answer.

Answer 1

Try this code

let Cities = new CsvProvider<"cities.csv">()
let cities = new Cities()
let firstRow = cities.Rows |> Seq.head