Capture Groups

FsGroup

FsGroup provides the functionality in the System.Text.RegularExpressions.Group Class, but returning arrays of objects instead of special collections and makes the group name a property.

anonymous groups

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open FsVerbalExpressions

let pattern = @"(\b(\w+?)[,:;]?\s?)+[?.!]"
let input = "This is one sentence. This is a second sentence."

let m = FsRegEx.firstMatch pattern input
printfn "Match: %s" m.Value

m.Groups()
|> Array.iteri (fun i g -> 
    printfn "   Group %i: '%s'" i g.Value
    g.Captures()
    |> Array.iteri (fun i c ->  
        printfn "      Capture %i: '%s'" i c.Value 
        )
    )

// Match: This is one sentence.
//    Group 0: 'This is one sentence.'
//        Capture 0: 'This is one sentence.'
//    Group 1: 'sentence'
//        Capture 0: 'This '
//        Capture 1: 'is '
//        Capture 2: 'one '
//        Capture 3: 'sentence'
//    Group 2: 'sentence'
//        Capture 0: 'This'
//        Capture 1: 'is'
//        Capture 2: 'one'
//        Capture 3: 'sentence'

named groups

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let pattern' = @"\b(?<FirstWord>\w+)\s?((\w+)\s)*(?<LastWord>\w+)?(?<Punctuation>\p{Po})"
let input' = "The cow jumped over the moon."

let m' = FsRegEx.firstMatch pattern' input'

printfn "Named Groups:"

m'.Groups()
|> Array.iter (fun g -> printfn "   %s: '%s'" g.Name g.Value)

// Named Groups:
//    0: 'The cow jumped over the moon.'
//    1: 'the '
//    2: 'the'
//    FirstWord: 'The'
//    LastWord: 'moon'
//    Punctuation: '.'

capturing groups

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let regExpr = @"\b(\w+?)([\u00AE\u2122])"

let matches = 
    "Microsoft® Office Professional Edition combines several office " +
        "productivity products, including Word, Excel®, Access®, Outlook®, " +
        "PowerPoint®, and several others. Some guidelines for creating " +
        "corporate documents using these productivity tools are available " +
        "from the documents created using Silverlight™ on the corporate " +
        "intranet site."
    |> FsRegEx.matches regExpr

matches
|> Array.iter (fun m ->
    let groups = m.Groups()
    printfn "%s: %s" groups.[2].Value groups.[1].Value)
                           
printfn ""
printfn "Found %i trademarks or registered trademarks." matches.Length

// ®: Microsoft
// ®: Excel
// ®: Access
// ®: Outlook
// ®: PowerPoint
// ™: Silverlight
//
// Found 6 trademarks or registered trademarks.

group numbers and names

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open System

let pattern'' = @"\b((?<word>\w+)\s*)+(?<end>[.?!])"
let input'' = "This is a sentence. This is a second sentence."

let groupNumbers' = FsRegEx.groupNumbers pattern''
let groupNames = FsRegEx.groupNames pattern''

let m'' = FsRegEx.firstMatch pattern'' input''

printfn "Match: %s" m''.Value

Array.zip groupNumbers' groupNames
|> Array.iter (fun (n, name) ->
    let isNumber, _ = Int32.TryParse(name)
    printfn "   Group %i%s: '%s'" 
        n 
        (if (not isNumber) then
            " (" + name + ")"
         else String.Empty)
        (m'.Groups()).[n].Value
    )

// Match: This is a sentence.
//    Group 0: 'This is a sentence.'
//    Group 1: 'sentence'
//    Group 2 (word): 'sentence'
//    Group 3 (end): '.'

namespace FsVerbalExpressions

val pattern : string

Full name: Group.pattern

val input : string

Full name: Group.input

val m : FsMatch

Full name: Group.m

module FsRegEx

from FsVerbalExpressions

val firstMatch : regularExpression:string -> input:string -> FsMatch

Full name: FsVerbalExpressions.FsRegEx.firstMatch

val printfn : format:Printf.TextWriterFormat<'T> -> 'T

Full name: Microsoft.FSharp.Core.ExtraTopLevelOperators.printfn

property FsMatch.Value: string

member FsMatch.Groups : unit -> FsGroup []

module Array

from Microsoft.FSharp.Collections

val iteri : action:(int -> 'T -> unit) -> array:'T [] -> unit

Full name: Microsoft.FSharp.Collections.Array.iteri

val i : int

val g : FsGroup

property FsGroup.Value: string

member FsGroup.Captures : unit -> System.Text.RegularExpressions.Capture []

val c : System.Text.RegularExpressions.Capture

property System.Text.RegularExpressions.Capture.Value: string

val pattern' : string

Full name: Group.pattern'

val input' : string

Full name: Group.input'

val m' : FsMatch

Full name: Group.m'

val iter : action:('T -> unit) -> array:'T [] -> unit

Full name: Microsoft.FSharp.Collections.Array.iter

property FsGroup.Name: string

val regExpr : string

Full name: Group.regExpr

val matches : FsMatch []

Full name: Group.matches

val matches : regularExpression:string -> input:string -> FsMatch []

Full name: FsVerbalExpressions.FsRegEx.matches

val m : FsMatch

val groups : FsGroup []

property System.Array.Length: int

namespace System

val pattern'' : string

Full name: Group.pattern''

val input'' : string

Full name: Group.input''

val groupNumbers' : int array

Full name: Group.groupNumbers'

val groupNumbers : regularExpression:string -> int array

Full name: FsVerbalExpressions.FsRegEx.groupNumbers

val groupNames : string array

Full name: Group.groupNames

val groupNames : regularExpression:string -> string array

Full name: FsVerbalExpressions.FsRegEx.groupNames

val m'' : FsMatch

Full name: Group.m''

type Array =
  member Clone : unit -> obj
  member CopyTo : array:Array * index:int -> unit + 1 overload
  member GetEnumerator : unit -> IEnumerator
  member GetLength : dimension:int -> int
  member GetLongLength : dimension:int -> int64
  member GetLowerBound : dimension:int -> int
  member GetUpperBound : dimension:int -> int
  member GetValue : [<ParamArray>] indices:int[] -> obj + 7 overloads
  member Initialize : unit -> unit
  member IsFixedSize : bool
  ...

Full name: System.Array

val zip : array1:'T1 [] -> array2:'T2 [] -> ('T1 * 'T2) []

Full name: Microsoft.FSharp.Collections.Array.zip

val n : int

val name : string

val isNumber : bool

type Int32 =
  struct
    member CompareTo : value:obj -> int + 1 overload
    member Equals : obj:obj -> bool + 1 overload
    member GetHashCode : unit -> int
    member GetTypeCode : unit -> TypeCode
    member ToString : unit -> string + 3 overloads
    static val MaxValue : int
    static val MinValue : int
    static member Parse : s:string -> int + 3 overloads
    static member TryParse : s:string * result:int -> bool + 1 overload
  end

Full name: System.Int32

Int32.TryParse(s: string, result: byref<int>) : bool
Int32.TryParse(s: string, style: Globalization.NumberStyles, provider: IFormatProvider, result: byref<int>) : bool

val not : value:bool -> bool

Full name: Microsoft.FSharp.Core.Operators.not

Multiple items
type String =
  new : value:char -> string + 7 overloads
  member Chars : int -> char
  member Clone : unit -> obj
  member CompareTo : value:obj -> int + 1 overload
  member Contains : value:string -> bool
  member CopyTo : sourceIndex:int * destination:char[] * destinationIndex:int * count:int -> unit
  member EndsWith : value:string -> bool + 2 overloads
  member Equals : obj:obj -> bool + 2 overloads
  member GetEnumerator : unit -> CharEnumerator
  member GetHashCode : unit -> int
  ...

Full name: System.String

--------------------
String(value: nativeptr<char>) : unit
String(value: nativeptr<sbyte>) : unit
String(value: char []) : unit
String(c: char, count: int) : unit
String(value: nativeptr<char>, startIndex: int, length: int) : unit
String(value: nativeptr<sbyte>, startIndex: int, length: int) : unit
String(value: char [], startIndex: int, length: int) : unit
String(value: nativeptr<sbyte>, startIndex: int, length: int, enc: Text.Encoding) : unit

field string.Empty

FSharpVerbalExpressions

Capture Groups

FsGroup

anonymous groups

named groups

capturing groups

group numbers and names