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Calculate left margins

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let margins (lines : seq<string>) =
    let marginWidth (line : string) =
        line.Length - line.TrimStart([|' '|]).Length 
    lines
    |> Seq.map (fun line -> marginWidth line)
    |> Seq.countBy (fun width -> width)
    |> Seq.filter (fun margCount -> fst(margCount) > 0)
    |> Seq.sortBy (fun margCount -> -snd(margCount))

// Example:
let lines = [
                "This has no margin."
                " This has a one-space margin."
                " So does this."
                "      These three lines have a six-space margin."
                "      Again with the six-space margin."
                "      And again."
                " Back to one space."
                "      And finally, another six space."
            ]

// Output: seq [(6, 4); (1, 3)]
lines |> margins

val margins : lines:seq<string> -> seq<int * int>

Full name: Script.margins

val lines : seq<string>

Multiple items
val seq : sequence:seq<'T> -> seq<'T>

Full name: Microsoft.FSharp.Core.Operators.seq

--------------------
type seq<'T> = System.Collections.Generic.IEnumerable<'T>

Full name: Microsoft.FSharp.Collections.seq<_>

Multiple items
val string : value:'T -> string

Full name: Microsoft.FSharp.Core.Operators.string

--------------------
type string = System.String

Full name: Microsoft.FSharp.Core.string

val marginWidth : (string -> int)

val line : string

property System.String.Length: int

System.String.TrimStart([<System.ParamArray>] trimChars: char []) : string

module Seq

from Microsoft.FSharp.Collections

val map : mapping:('T -> 'U) -> source:seq<'T> -> seq<'U>

Full name: Microsoft.FSharp.Collections.Seq.map

val countBy : projection:('T -> 'Key) -> source:seq<'T> -> seq<'Key * int> (requires equality)

Full name: Microsoft.FSharp.Collections.Seq.countBy

val width : int

val filter : predicate:('T -> bool) -> source:seq<'T> -> seq<'T>

Full name: Microsoft.FSharp.Collections.Seq.filter

val margCount : int * int

val fst : tuple:('T1 * 'T2) -> 'T1

Full name: Microsoft.FSharp.Core.Operators.fst

val sortBy : projection:('T -> 'Key) -> source:seq<'T> -> seq<'T> (requires comparison)

Full name: Microsoft.FSharp.Collections.Seq.sortBy

val snd : tuple:('T1 * 'T2) -> 'T2

Full name: Microsoft.FSharp.Core.Operators.snd

val lines : string list

Full name: Script.lines

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Link:	http://fssnip.net/9J
Posted:	14 years ago
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