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Decompose an Array to a Tuple after a Forward Pipe
f#

So I'm reading the contents of a character seperated text file and I'm using a sequence as follows:

let file = seq {

let reader = new StreamReader(htmlEntities)

while not reader.EndOfStream do

yield reader.ReadLine() |> String.split ['\t'] |> ?

done

}

There are 2 columns in the file and I'd like to return a two element tuple. Is there a slick way to decompose the array to a tuple after a forward pipe? I know match will decompose it but not right after the forward pipe (At least as far as I can tell). I guess I could do this but I was thinking there may be a simpler way:

yield reader.ReadLine() |> String.split ['\t'] |> (fun a -> (a.[0],a.[1]))

I'm sure there is a simple answer but I cant seem to find it.

TIA,

m

.

The only cute ways I can think of are

let arr = [|1;2|]

let way1 = arr |> function [|a;b|] -> (a,b)

let way2 = arr |> fun a -> a.[0], a.[1]

By on 8/20/2009 8:50 AM ()

Ok, thanks!

By on 8/20/2009 9:02 AM ()

A similar problem:

How to apply 2 functions to the same seq.

assume you have s=seq<float>, is there some op that works as follows:

s |> op (Seq.min,Seq.max) ,

would yield same as

Seq.min s, Seq.max s

Thanks a lot

By on 8/21/2009 1:54 PM ()

(web coding, have not compiled)

let op (f,g) x = f x, g x

seems to do it.

Of course this traverses the sequence twice in your example; you'd need f and g to both be folds in order to be able to combine both operations into a single sequence traversal.

By on 8/21/2009 3:11 PM ()

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