microsoft-visualbasic-runtime/ComponentModel/DataStructures/Set/SetsExtension.vb

#Region "Microsoft.VisualBasic::a4669d3f6b37325ad6e91207ea10da89, Microsoft.VisualBasic.Core\ComponentModel\DataStructures\Set\SetsExtension.vb"

    ' Author:
    ' 
    '       asuka (amethyst.asuka@gcmodeller.org)
    '       xie (genetics@smrucc.org)
    '       xieguigang (xie.guigang@live.com)
    ' 
    ' Copyright (c) 2018 GPL3 Licensed
    ' 
    ' 
    ' GNU GENERAL PUBLIC LICENSE (GPL3)
    ' 
    ' 
    ' This program is free software: you can redistribute it and/or modify
    ' it under the terms of the GNU General Public License as published by
    ' the Free Software Foundation, either version 3 of the License, or
    ' (at your option) any later version.
    ' 
    ' This program is distributed in the hope that it will be useful,
    ' but WITHOUT ANY WARRANTY; without even the implied warranty of
    ' MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    ' GNU General Public License for more details.
    ' 
    ' You should have received a copy of the GNU General Public License
    ' along with this program. If not, see <http://www.gnu.org/licenses/>.



    ' /********************************************************************************/

    ' Summaries:

    ' Module SetsExtension
    ' 
    '     Function: (+2 Overloads) AsSet, Except, Intersection, (+3 Overloads) ToArray, Union
    ' 
    ' /********************************************************************************/

#End Region

Imports System.Runtime.CompilerServices
Imports Microsoft.VisualBasic.CommandLine.Reflection
Imports Microsoft.VisualBasic.ComponentModel.DataStructures

Public Module SetsExtension

    <MethodImpl(MethodImplOptions.AggressiveInlining)>
    <Extension> Public Function ToArray(Of T)(s As [Set], [ctype] As Func(Of Object, T)) As T()
        Return s.ToArray _
                .Select([ctype]) _
                .ToArray
    End Function

    ''' <summary>
    ''' DirectCast
    ''' </summary>
    ''' <typeparam name="T"></typeparam>
    ''' <returns></returns>
    ''' 
    <MethodImpl(MethodImplOptions.AggressiveInlining)>
    <Extension> Public Function ToArray(Of T)(s As [Set]) As T()
        Return s.ToArray _
                .Select(Function(x) DirectCast(x, T)) _
                .ToArray
    End Function

#Region "API"

    ''' <summary>
    ''' 差集，函数会从<paramref name="s1"/>集合之中删除<paramref name="s2"/>中共同的元素
    ''' </summary>
    ''' <param name="s1"></param>
    ''' <param name="s2"></param>
    ''' <returns></returns>
    <MethodImpl(MethodImplOptions.AggressiveInlining)>
    <ExportAPI("Except")>
    Public Function Except(s1 As [Set], s2 As [Set]) As [Set]
        Return s1 - s2
    End Function

    ''' <summary>
    ''' Performs a union of two sets.
    ''' (就并集)
    ''' </summary>
    ''' <param name="s1"></param>
    ''' <param name="s2"></param>
    ''' <returns></returns>
    <MethodImpl(MethodImplOptions.AggressiveInlining)>
    <ExportAPI("Union")>
    Public Function Union(s1 As [Set], s2 As [Set]) As [Set]
        Return s1 Or s2
    End Function

    ''' <summary>
    ''' Performs an intersection of two sets.
    ''' (求交集)
    ''' </summary>
    ''' <param name="s1"></param>
    ''' <param name="s2"></param>
    ''' <returns></returns>
    <MethodImpl(MethodImplOptions.AggressiveInlining)>
    <ExportAPI("Intersection")>
    Public Function Intersection(s1 As [Set], s2 As [Set]) As [Set]
        Return s1 And s2
    End Function

    ''' <summary>
    ''' 将任意序列转换为集合类型
    ''' </summary>
    ''' <param name="source"></param>
    ''' <returns></returns>
    <MethodImpl(MethodImplOptions.AggressiveInlining)>
    <ExportAPI("As.Set")>
    <Extension>
    Public Function AsSet(source As IEnumerable) As [Set]
        Return New [Set](source)
    End Function

    <ExportAPI("As.Array")>
    Public Function ToArray([set] As [Set]) As Object()
        Return [set].ToArray
    End Function

    ''' <summary>
    ''' Create a string set
    ''' </summary>
    ''' <param name="strings"></param>
    ''' <returns></returns>
    <MethodImpl(MethodImplOptions.AggressiveInlining)>
    <Extension>
    Public Function AsSet(strings As IEnumerable(Of String)) As StringSet
        Return New StringSet(strings)
    End Function
#End Region
End Module