Using Seq functions on an IEnumerable
f#, ienumerable
Solution
F#'s type `seq<'a>` is equivalent to the generic `IEnumerable<'a>` in `System.Collections.Generic`, but not to the non-generic `IEnumerable`. You can use the `Seq.cast<'a>` function to convert from the non-generic one to the generic one:
let foo = myHtmlElementCollection
|> Seq.cast<HtmlElement>
|> Seq.find (fun i -> i.Name = "foo")
Problem
I'm trying to apply Seq functions on an IEnumerable. More specifically, it's `System.Windows.Forms.HtmlElementCollection` which implements `ICollection` and `IEnumerable`. Since an F# `seq` is an IEnumerable, I thought I could write ``` let foo = myHtmlElementCollection |> Seq.find (fun i -> i.Name = "foo") ``` but the compiler will have none of it, and complains that "The type 'HtmlElementCollection' is not compatible with the type 'seq<'a>'". However, the compiler willingly accepts the IEnumerable in a `for .. in ..` sequence expression: ``` let foo = seq { for i in myHtmlElementCollection -> i } |> Seq.find (fun i -> i.Name = "foo") ``` What do I need to do in order for the IEnumerable to be treated just like any old F# `seq`? NB: This question is marked as a duplicate, but it's not. The linked "duplicate" is about untyped sequences (a seq from the seq { for ... } expression), whereas my question is about typed sequences.