Tuple<T1,T2,T3,T4,T5,T6,T7>.IStructuralEquatable.Equals Method

Reference

Definition

Namespace:: System

Assembly:: System.Runtime.dll

Assembly:: mscorlib.dll

Assembly:: netstandard.dll

Source:: Tuple.cs

Source:: Tuple.cs

Source:: Tuple.cs

Important

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Returns a value that indicates whether the current Tuple<T1,T2,T3,T4,T5,T6,T7> object is equal to a specified object based on a specified comparison method.

 virtual bool System.Collections.IStructuralEquatable.Equals(System::Object ^ other, System::Collections::IEqualityComparer ^ comparer) = System::Collections::IStructuralEquatable::Equals;

bool IStructuralEquatable.Equals (object other, System.Collections.IEqualityComparer comparer);

abstract member System.Collections.IStructuralEquatable.Equals : obj * System.Collections.IEqualityComparer -> bool
override this.System.Collections.IStructuralEquatable.Equals : obj * System.Collections.IEqualityComparer -> bool

Function Equals (other As Object, comparer As IEqualityComparer) As Boolean Implements IStructuralEquatable.Equals

Parameters

other: Object

The object to compare with this instance.

comparer: IEqualityComparer

An object that defines the method to use to evaluate whether the two objects are equal.

Returns

Boolean

true if the current instance is equal to the specified object; otherwise, false.

Implements

Equals(Object, IEqualityComparer)

Examples

The following example defines a RateComparer class that performs a custom test for equality. If the values that are passed to its IStructuralEquatable.Equals method are of type Single or Double, the method tests for equality by using only up to three fractional digits. Otherwise, it simply calls the x parameter's Equals method. The example uses this IEqualityComparer implementation to determine whether four Tuple<T1,T2,T3,T4,T5,T6,T7> objects that contain data on the rate of population change between 1950 and 2000 are equal.

using System;
using System.Collections;

public class RateComparer<T1, T2, T3, T4, T5, T6, T7> : IEqualityComparer
{
   private int argument = 0;

   public new bool Equals(object x, object y)
   {
      argument++;
      if (argument == 1) return true;

      double fx, fy;
      if (x is Double || x is Single)
      {
            fx = (double) x;
            fy = (double) y;
            return Math.Round(fx * 1000).Equals(Math.Round(fy * 1000));
      }
      else
      {
         return x.Equals(y);
      }
   }

   public int GetHashCode(object obj)
   {
      if (obj is Single || obj is Double)
         return Math.Round(((double) obj) * 1000).GetHashCode();
      else
         return obj.GetHashCode();
   }
}

public class Example
{
   public static void Main()
   {
      var rate1 = Tuple.Create("New York", -.013934, .014505,
                               -.1042733, .0354833, .093644, .0290792);
      var rate2 = Tuple.Create("Unknown City", -.013934, .014505,
                               -.1042733, .0354833, .093644, .0290792);
      var rate3 = Tuple.Create("Unknown City", -.013934, .014505,
                               -.1042733, .0354833, .093644, .029079);
      var rate4 = Tuple.Create("San Francisco", -.0451934, -.0332858,
                               -.0512803, .0662544, .0728964, .0491912);
      IStructuralEquatable eq = rate1;
      // Compare first tuple with remaining two tuples.
      Console.WriteLine("{0} = ", rate1.ToString());
      Console.WriteLine("   {0} : {1}", rate2,
                        eq.Equals(rate2, new RateComparer<string, double, double, double, double, double, double>()));
      Console.WriteLine("   {0} : {1}", rate3,
                        eq.Equals(rate3, new RateComparer<string, double, double, double, double, double, double>()));
      Console.WriteLine("   {0} : {1}", rate4,
                        eq.Equals(rate4, new RateComparer<string, double, double,double,  double, double, double>()));
   }
}
// The example displays the following output:
//    (New York, -0.013934, 0.014505, -0.1042733, 0.0354833, 0.093644, 0.0290792) =
//       (Unknown City, -0.013934, 0.014505, -0.1042733, 0.0354833, 0.093644, 0.0290792) : True
//       (Unknown City, -0.013934, 0.014505, -0.1042733, 0.0354833, 0.093644, 0.029079) : True
//       (San Francisco, -0.0451934, -0.0332858, -0.0512803, 0.0662544, 0.0728964, 0.0491912) : False

open System
open System.Collections

type RateComparer<'T1, 'T2, 'T3, 'T4, 'T5, 'T6, 'T7>() =
    let mutable argument = 0

    interface IEqualityComparer with
        member _.Equals(x, y) =
            argument <- argument + 1
            if argument = 1 then
                true
            else
                if x :? Double || x :? Single then
                    let fx = x :?> double
                    let fy = y :?> double
                    Math.Round(fx * 1000.).Equals(Math.Round(fy * 1000.))
                else
                    x.Equals y

        member _.GetHashCode(obj) =
            if obj :? Single || obj :? Double then
                Math.Round((obj :?> double) * 1000.).GetHashCode()
            else
                obj.GetHashCode()

let rate1 = Tuple.Create("New York", -0.013934, 0.014505, -0.1042733, 0.0354833, 0.093644, 0.0290792)
let rate2 = Tuple.Create("Unknown City", -0.013934, 0.014505, -0.1042733, 0.0354833, 0.093644, 0.0290792)
let rate3 = Tuple.Create("Unknown City", -0.013934, 0.014505, -0.1042733, 0.0354833, 0.093644, 0.029079)
let rate4 = Tuple.Create("San Francisco", -0.0451934, -0.0332858, -0.0512803, 0.0662544, 0.0728964, 0.0491912)
let eq: IStructuralEquatable = rate1
// Compare first tuple with remaining two tuples.
printfn $"{rate1} = "
printfn $"   {rate2} : {eq.Equals(rate2, RateComparer<string, double, double, double, double, double, double>())}"
printfn $"   {rate3} : {eq.Equals(rate3, RateComparer<string, double, double, double, double, double, double>())}"
printfn $"   {rate4} : {eq.Equals(rate4, RateComparer<string, double, double,double,  double, double, double>())}"
// The example displays the following output:
//    (New York, -0.013934, 0.014505, -0.1042733, 0.0354833, 0.093644, 0.0290792) =
//       (Unknown City, -0.013934, 0.014505, -0.1042733, 0.0354833, 0.093644, 0.0290792) : True
//       (Unknown City, -0.013934, 0.014505, -0.1042733, 0.0354833, 0.093644, 0.029079) : True
//       (San Francisco, -0.0451934, -0.0332858, -0.0512803, 0.0662544, 0.0728964, 0.0491912) : False

Imports System.Collections

Public Class RateComparer(Of T1, T2, T3, T4, T5, T6, T7) : Implements IEqualityComparer
   Private argument As Integer = 0

   Public Overloads Function Equals(x As Object, y As Object) As Boolean _
                   Implements IEqualityComparer.Equals
      argument += 1
      If argument = 1 Then
         Return True
      Else
         Dim fx, fy As Double
         If typeof x Is Double Or typeof x Is Single Then
            fx = CDbl(x)
            fy = CDbl(y)
            Return Math.Round(fx * 1000).Equals(Math.Round(fy * 1000))
         Else
            Return x.Equals(y)
         End If
      End If   
   End Function
   
   Public Overloads Function GetHashCode(obj As Object) As Integer _
                    Implements IEqualityComparer.GetHashCode
      If TypeOf(obj) Is Single Or TypeOf(obj) Is Double Then
         Return Math.Round(CDbl(obj) * 1000).GetHashCode()
      Else
         Return obj.GetHashCode()
      End If
   End Function                
End Class

Module Example
   Public Sub Main()
      Dim rate1 = Tuple.Create("New York", -.013934, .014505, 
                               -.1042733, .0354833, .093644, .0290792)
      Dim rate2 = Tuple.Create("Unknown City", -.013934, .014505, 
                               -.1042733, .0354833, .093644, .0290792)
      Dim rate3 = Tuple.Create("Unknown City", -.013934, .014505, 
                               -.1042733, .0354833, .093644, .029079)
      Dim rate4 = Tuple.Create("San Francisco", -.0451934, -.0332858, 
                               -.0512803, .0662544, .0728964, .0491912)
      Dim eq As IStructuralEquatable = rate1
      ' Compare first tuple with remaining two tuples.
      Console.WriteLine("{0} = ", rate1.ToString())
      Console.WriteLine("   {0} : {1}", rate2, 
                        eq.Equals(rate2, New RateComparer(Of String, Double, Double, Double, Double, Double, Double)()))
      Console.WriteLine("   {0} : {1}", rate3, 
                        eq.Equals(rate3, New RateComparer(Of String, Double, Double, Double, Double, Double, Double)()))
      Console.WriteLine("   {0} : {1}", rate4, 
                        eq.Equals(rate4, New RateComparer(Of String, Double, Double, Double, Double, Double, Double)()))
   End Sub
End Module
' The example displays the following output:
'    (New York, -0.013934, 0.014505, -0.1042733, 0.0354833, 0.093644, 0.0290792) =
'       (Unknown City, -0.013934, 0.014505, -0.1042733, 0.0354833, 0.093644, 0.0290792) : True
'       (Unknown City, -0.013934, 0.014505, -0.1042733, 0.0354833, 0.093644, 0.029079) : True
'       (San Francisco, -0.0451934, -0.0332858, -0.0512803, 0.0662544, 0.0728964, 0.0491912) : False

Remarks

This member is an explicit interface member implementation. It can be used only when the Tuple<T1,T2,T3,T4,T5,T6,T7> instance is cast to an IStructuralEquatable interface.

The IEqualityComparer.Equals implementation is called only if other is not null, and if it can be successfully cast (in C#) or converted (in Visual Basic) to a Tuple<T1,T2,T3,T4,T5,T6,T7> object whose components are of the same types as the current instance. The IStructuralEquatable.Equals(Object, IEqualityComparer) method first passes the Item1 values of the Tuple<T1,T2,T3,T4,T5,T6,T7> objects to be compared to the IEqualityComparer.Equals implementation. If this method call returns true, the method is called again and passed the Item2 values of the two Tuple<T1,T2,T3,T4,T5,T6,T7> objects. This continues until the method call returns false when it compares a specific pair of Item values, or the two Item7 values are passed to the method.

Applies to

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