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Convert each element of a sequence and ignore exception throw
f#

I have a seq of strings and they should all be valid Uri. But some are wrong and so when I do System.Uri elem i get an exception thrown. The below code try to convert each element and ignores the ones that through an exception during converions.Does someone have a better suggestion to do this ?

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let convert fConvert s =


    s|> Seq.map( fun elem -> try


                                              

                                     Some( fConvert elem)


                                          

                                 with


                                          

                                 | _ as ex -> Console.WriteLine(ex.Message); None )


    

         |> Seq.filter( fun elem -> elem.IsSome )


    

         |> Seq.map( fun elem -> elem.Value )

Thanks !!

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I might write it like this:

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let exceptionToOption f x =
    try Some(f x)
    with _ -> None

let convert fConvert s =
    s |> Seq.map (exceptionToOption fConvert)
      |> Seq.choose id

convert System.Int32.Parse ["1"; "two"; "3"]
|> printfn "%A"
By on 4/30/2010 6:11 PM ()Reply
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Brian,

I'd simplify that to:

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let convert fConvert s =
    s |> Seq.choose (exceptionToOption fConvert)
By on 4/30/2010 7:14 PM ()Reply
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That looks okay to me. One improvement would be to use Seq.choose in place of the last two pipes.

By on 4/30/2010 4:55 PM ()Reply

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