Comparison<T> 대리자
정의
중요
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형식이 같은 두 개체를 비교하는 메서드를 나타냅니다.
generic <typename T>
public delegate int Comparison(T x, T y);public delegate int Comparison<in T>(T x, T y);public delegate int Comparison<T>(T x, T y);type Comparison<'T> = delegate of 'T * 'T -> intPublic Delegate Function Comparison(Of In T)(x As T, y As T) As Integer Public Delegate Function Comparison(Of T)(x As T, y As T) As Integer 형식 매개 변수
- T
비교할 개체의 형식입니다.
이 형식 매개 변수는 반공변(Contravariant)입니다. 즉, 지정한 형식이나 더 적게 파생된 모든 형식을 사용할 수 있습니다. 공변성(Covariance) 및 반공변성(Contravariance)에 대한 자세한 내용은 제네릭의 공변성(Covariance) 및 반공변성(Contravariance)을 참조하세요.매개 변수
- x
- T
비교할 첫 번째 개체입니다.
- y
- T
비교할 두 번째 개체입니다.
반환 값
다음 표와 같이 x 및 y의 상대 값을 나타내는 부호 있는 정수입니다.
| 값 | 의미 |
|---|---|
| 0보다 작음 | x가 y보다 작은 경우
|
| 0 | x가 y와 같습니다.
|
| 0보다 큼 | x가 y보다 큰 경우
|
예제
다음 코드 예제에서는 메서드 오버로드와 Comparison<T> 함께 대리자를 사용하는 방법을 Sort(Comparison<T>) 보여 줍니다.
코드 예제에서는 문자열 CompareDinosByLength에 대한 대체 비교 메서드를 정의합니다. 이 메서드는 다음과 같이 작동합니다. 첫째, 비교가 테스트 null되고 null 참조가 null이 아닌 참조보다 작은 것으로 처리됩니다. 둘째, 문자열 길이를 비교하고 더 긴 문자열은 더 큰 것으로 간주됩니다. 셋째, 길이가 같으면 일반 문자열 비교가 사용됩니다.
문자열 중 하나는 List<T> 특정 순서 없이 4개의 문자열로 만들어지고 채워집니다. 목록에는 빈 문자열과 null 참조도 포함됩니다. 목록이 표시되고, 메서드를 나타내는 CompareDinosByLength 제네릭 대리자를 Comparison<T> 사용하여 정렬되고, 다시 표시됩니다.
using namespace System;
using namespace System::Collections::Generic;
int CompareDinosByLength(String^ x, String^ y)
{
if (x == nullptr)
{
if (y == nullptr)
{
// If x is null and y is null, they're
// equal.
return 0;
}
else
{
// If x is null and y is not null, y
// is greater.
return -1;
}
}
else
{
// If x is not null...
//
if (y == nullptr)
// ...and y is null, x is greater.
{
return 1;
}
else
{
// ...and y is not null, compare the
// lengths of the two strings.
//
int retval = x->Length.CompareTo(y->Length);
if (retval != 0)
{
// If the strings are not of equal length,
// the longer string is greater.
//
return retval;
}
else
{
// If the strings are of equal length,
// sort them with ordinary string comparison.
//
return x->CompareTo(y);
}
}
}
};
void Display(List<String^>^ list)
{
Console::WriteLine();
for each(String^ s in list)
{
if (s == nullptr)
Console::WriteLine("(null)");
else
Console::WriteLine("\"{0}\"", s);
}
};
void main()
{
List<String^>^ dinosaurs = gcnew List<String^>();
dinosaurs->Add("Pachycephalosaurus");
dinosaurs->Add("Amargasaurus");
dinosaurs->Add("");
dinosaurs->Add(nullptr);
dinosaurs->Add("Mamenchisaurus");
dinosaurs->Add("Deinonychus");
Display(dinosaurs);
Console::WriteLine("\nSort with generic Comparison<String^> delegate:");
dinosaurs->Sort(
gcnew Comparison<String^>(CompareDinosByLength));
Display(dinosaurs);
}
/* This code example produces the following output:
"Pachycephalosaurus"
"Amargasaurus"
""
(null)
"Mamenchisaurus"
"Deinonychus"
Sort with generic Comparison<String^> delegate:
(null)
""
"Deinonychus"
"Amargasaurus"
"Mamenchisaurus"
"Pachycephalosaurus"
*/
using System;
using System.Collections.Generic;
public class Example
{
private static int CompareDinosByLength(string x, string y)
{
if (x == null)
{
if (y == null)
{
// If x is null and y is null, they're
// equal.
return 0;
}
else
{
// If x is null and y is not null, y
// is greater.
return -1;
}
}
else
{
// If x is not null...
//
if (y == null)
// ...and y is null, x is greater.
{
return 1;
}
else
{
// ...and y is not null, compare the
// lengths of the two strings.
//
int retval = x.Length.CompareTo(y.Length);
if (retval != 0)
{
// If the strings are not of equal length,
// the longer string is greater.
//
return retval;
}
else
{
// If the strings are of equal length,
// sort them with ordinary string comparison.
//
return x.CompareTo(y);
}
}
}
}
public static void Main()
{
List<string> dinosaurs = new List<string>();
dinosaurs.Add("Pachycephalosaurus");
dinosaurs.Add("Amargasaurus");
dinosaurs.Add("");
dinosaurs.Add(null);
dinosaurs.Add("Mamenchisaurus");
dinosaurs.Add("Deinonychus");
Display(dinosaurs);
Console.WriteLine("\nSort with generic Comparison<string> delegate:");
dinosaurs.Sort(CompareDinosByLength);
Display(dinosaurs);
}
private static void Display(List<string> list)
{
Console.WriteLine();
foreach( string s in list )
{
if (s == null)
Console.WriteLine("(null)");
else
Console.WriteLine("\"{0}\"", s);
}
}
}
/* This code example produces the following output:
"Pachycephalosaurus"
"Amargasaurus"
""
(null)
"Mamenchisaurus"
"Deinonychus"
Sort with generic Comparison<string> delegate:
(null)
""
"Deinonychus"
"Amargasaurus"
"Mamenchisaurus"
"Pachycephalosaurus"
*/
open System
let compareDinosByLength (x: string) (y: string) =
match x with
| null when isNull y ->
// If x is null and y is null, they're equal.
0
| null ->
// If x is null and y is not null, y is greater.
-1
| _ when isNull y->
// If x is not null and y is null, x is greater.
1
| _ ->
// If x is not null and y is not null, compare the lengths of the two strings.
let retval = x.Length.CompareTo y.Length
if retval <> 0 then
// If the strings are not of equal length, the longer string is greater.
retval
else
// If the strings are of equal length, sort them with ordinary string comparison.
x.CompareTo y
let display list =
printfn ""
for s in list do
if isNull s then
printfn "(null)"
else
printfn $"\"%s{s}\""
let dinosaurs = ResizeArray()
dinosaurs.Add "Pachycephalosaurus"
dinosaurs.Add "Amargasaurus"
dinosaurs.Add ""
dinosaurs.Add null
dinosaurs.Add "Mamenchisaurus"
dinosaurs.Add "Deinonychus"
display dinosaurs
printfn "\nSort with generic Comparison<string> delegate:"
dinosaurs.Sort compareDinosByLength
display dinosaurs
// This code example produces the following output:
//
// "Pachycephalosaurus"
// "Amargasaurus"
// ""
// (null)
// "Mamenchisaurus"
// "Deinonychus"
//
// Sort with generic Comparison<string> delegate:
//
// (null)
// ""
// "Deinonychus"
// "Amargasaurus"
// "Mamenchisaurus"
// "Pachycephalosaurus"
Imports System.Collections.Generic
Public Class Example
Private Shared Function CompareDinosByLength( _
ByVal x As String, ByVal y As String) As Integer
If x Is Nothing Then
If y Is Nothing Then
' If x is Nothing and y is Nothing, they're
' equal.
Return 0
Else
' If x is Nothing and y is not Nothing, y
' is greater.
Return -1
End If
Else
' If x is not Nothing...
'
If y Is Nothing Then
' ...and y is Nothing, x is greater.
Return 1
Else
' ...and y is not Nothing, compare the
' lengths of the two strings.
'
Dim retval As Integer = _
x.Length.CompareTo(y.Length)
If retval <> 0 Then
' If the strings are not of equal length,
' the longer string is greater.
'
Return retval
Else
' If the strings are of equal length,
' sort them with ordinary string comparison.
'
Return x.CompareTo(y)
End If
End If
End If
End Function
Public Shared Sub Main()
Dim dinosaurs As New List(Of String)
dinosaurs.Add("Pachycephalosaurus")
dinosaurs.Add("Amargasaurus")
dinosaurs.Add("")
dinosaurs.Add(Nothing)
dinosaurs.Add("Mamenchisaurus")
dinosaurs.Add("Deinonychus")
Display(dinosaurs)
Console.WriteLine(vbLf & "Sort with generic Comparison(Of String) delegate:")
dinosaurs.Sort(AddressOf CompareDinosByLength)
Display(dinosaurs)
End Sub
Private Shared Sub Display(ByVal lis As List(Of String))
Console.WriteLine()
For Each s As String In lis
If s Is Nothing Then
Console.WriteLine("(Nothing)")
Else
Console.WriteLine("""{0}""", s)
End If
Next
End Sub
End Class
' This code example produces the following output:
'
'"Pachycephalosaurus"
'"Amargasaurus"
'""
'(Nothing)
'"Mamenchisaurus"
'"Deinonychus"
'
'Sort with generic Comparison(Of String) delegate:
'
'(Nothing)
'""
'"Deinonychus"
'"Amargasaurus"
'"Mamenchisaurus"
'"Pachycephalosaurus"
다음 예제에서는 대리자를 Comparison<T> 사용하여 개체 컬렉션 CityInfo 의 요소를 정렬합니다. CityInfo 도시 및 해당 인구에 대 한 정보를 포함 하는 애플리케이션 정의 클래스가입니다. 이 예제에서는 개체의 순서를 지정하는 세 가지 방법을 제공하는 세 가지 메서드CompareByName``CompareByPopulation를 정의합니다CompareByNames.CityInfo 각 메서드는 메서드의 comparison 인수에 Array.Sort<T>(T[], Comparison<T>) 할당됩니다.
using System;
public class CityInfo
{
string cityName;
string countryName;
int pop2010;
public CityInfo(string name, string country, int pop2010)
{
this.cityName = name;
this.countryName = country;
this.pop2010 = pop2010;
}
public string City
{ get { return this.cityName; } }
public string Country
{ get { return this.countryName; } }
public int Population
{ get { return this.pop2010; } }
public static int CompareByName(CityInfo city1, CityInfo city2)
{
return String.Compare(city1.City, city2.City);
}
public static int CompareByPopulation(CityInfo city1, CityInfo city2)
{
return city1.Population.CompareTo(city2.Population);
}
public static int CompareByNames(CityInfo city1, CityInfo city2)
{
return String.Compare(city1.Country + city1.City, city2.Country + city2.City);
}
}
public class Example
{
public static void Main()
{
CityInfo NYC = new CityInfo("New York City", "United States of America", 8175133 );
CityInfo Det = new CityInfo("Detroit", "United States of America", 713777);
CityInfo Paris = new CityInfo("Paris", "France", 2193031);
CityInfo[] cities = { NYC, Det, Paris };
// Display ordered array.
DisplayArray(cities);
// Sort array by city name.
Array.Sort(cities, CityInfo.CompareByName);
DisplayArray(cities);
// Sort array by population.
Array.Sort(cities, CityInfo.CompareByPopulation);
DisplayArray(cities);
// Sort array by country + city name.
Array.Sort(cities, CityInfo.CompareByNames);
DisplayArray(cities);
}
private static void DisplayArray(CityInfo[] cities)
{
Console.WriteLine("{0,-20} {1,-25} {2,10}", "City", "Country", "Population");
foreach (var city in cities)
Console.WriteLine("{0,-20} {1,-25} {2,10:N0}", city.City,
city.Country, city.Population);
Console.WriteLine();
}
}
// The example displays the following output:
// City Country Population
// New York City United States of America 8,175,133
// Detroit United States of America 713,777
// Paris France 2,193,031
//
// City Country Population
// Detroit United States of America 713,777
// New York City United States of America 8,175,133
// Paris France 2,193,031
//
// City Country Population
// Detroit United States of America 713,777
// Paris France 2,193,031
// New York City United States of America 8,175,133
//
// City Country Population
// Paris France 2,193,031
// Detroit United States of America 713,777
// New York City United States of America 8,175,133
open System
type CityInfo =
{ City: string
Country: string
Population: int }
static member CompareByName city1 city2 =
String.Compare(city1.City, city2.City)
static member CompareByPopulation city1 city2 =
city1.Population.CompareTo city2.Population
static member CompareByNames city1 city2 =
String.Compare(city1.Country + city1.City, city2.Country + city2.City)
let display cities =
printfn $"""{"City",-20} {"Country",-25} {"Population",10}"""
for city in cities do
printfn $"{city.City,-20} {city.Country,-25} {city.Population,10:N0}"
printfn ""
let NYC = { City = "New York City"; Country = "United States of America"; Population = 8175133 }
let Det = { City = "Detroit"; Country = "United States of America"; Population = 713777 }
let Paris = { City = "Paris"; Country = "France"; Population = 2193031 }
let cities = [| NYC; Det; Paris |]
// Display ordered array.
display cities
// Sort array by city name.
Array.Sort(cities, CityInfo.CompareByName)
display cities
// Sort array by population.
Array.Sort(cities, CityInfo.CompareByPopulation);
display cities
// Sort array by country + city name.
Array.Sort(cities, CityInfo.CompareByNames);
display cities
// The example displays the following output:
// City Country Population
// New York City United States of America 8,175,133
// Detroit United States of America 713,777
// Paris France 2,193,031
//
// City Country Population
// Detroit United States of America 713,777
// New York City United States of America 8,175,133
// Paris France 2,193,031
//
// City Country Population
// Detroit United States of America 713,777
// Paris France 2,193,031
// New York City United States of America 8,175,133
//
// City Country Population
// Paris France 2,193,031
// Detroit United States of America 713,777
// New York City United States of America 8,175,133
Public Class CityInfo
Dim cityName As String
Dim countryName As String
Dim pop2010 As Integer
Public Sub New(name As String, country As String, pop2010 As Integer)
Me.cityName = name
Me.countryName = country
Me.pop2010 = pop2010
End Sub
Public ReadOnly Property City As String
Get
Return Me.cityName
End Get
End Property
Public ReadOnly Property Country As String
Get
Return Me.countryName
End Get
End Property
Public ReadOnly Property Population As Integer
Get
Return Me.pop2010
End Get
End Property
Public Shared Function CompareByName(city1 As CityInfo, city2 As CityInfo) As Integer
Return String.Compare(city1.City, city2.City)
End Function
Public Shared Function CompareByPopulation(city1 As CityInfo, city2 As CityInfo) As Integer
Return city1.Population.CompareTo(city2.Population)
End Function
Public Shared Function CompareByNames(city1 As CityInfo, city2 As CityInfo) As Integer
Return String.Compare(city1.Country + city1.City, city2.Country + city2.City)
End Function
End Class
Module Example
Public Sub Main()
Dim NYC As New CityInfo("New York City", "United States of America", 8175133)
Dim Det As New CityInfo("Detroit", "United States of America", 713777)
Dim Paris As New CityInfo("Paris", "France", 2193031)
Dim cities As CityInfo() = { NYC, Det, Paris }
' Display ordered array.
DisplayArray(cities)
' Sort array by city name.
Array.Sort(cities, AddressOf CityInfo.CompareByName)
DisplayArray(cities)
' Sort array by population.
Array.Sort(cities, AddressOf CityInfo.CompareByPopulation)
DisplayArray(cities)
' Sort array by country + city name.
Array.Sort(cities, AddressOf CityInfo.CompareByNames)
DisplayArray(cities)
End Sub
Private Sub DisplayArray(cities() As CityInfo)
Console.WriteLine("{0,-20} {1,-25} {2,10}", "City", "Country/Region", "Population")
For Each city In cities
Console.WriteLine("{0,-20} {1,-25} {2,10:N0}", city.City, city.Country, city.Population)
Next
Console.WriteLine()
End Sub
End Module
' The example displays the following output:
' City Country/Region Population
' New York City United States of America 8,175,133
' Detroit United States of America 713,777
' Paris France 2,193,031
'
' City Country/Region Population
' Detroit United States of America 713,777
' New York City United States of America 8,175,133
' Paris France 2,193,031
'
' City Country/Region Population
' Detroit United States of America 713,777
' Paris France 2,193,031
' New York City United States of America 8,175,133
'
' City Country/Region Population
' Paris France 2,193,031
' Detroit United States of America 713,777
' New York City United States of America 8,175,133
설명
이 대리자는 클래스의 Array 메서드 오버로드와 Sort(Comparison<T>) 클래스의 List<T> 메서드 오버로드에서 배열 또는 목록의 요소를 정렬하는 데 사용됩니다Sort<T>(T[], Comparison<T>).
확장 메서드
| GetMethodInfo(Delegate) |
지정된 대리자가 나타내는 메서드를 나타내는 개체를 가져옵니다. |