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Single.Equals Method

  • Reference

Definition

Namespace:
System
Assembly:
System.Runtime.dll
Assembly:
mscorlib.dll
Assembly:
netstandard.dll

Returns a value indicating whether two instances of Single represent the same value.

Overloads

Equals(Object)

Returns a value indicating whether this instance is equal to a specified object.
Equals(Single)

Returns a value indicating whether this instance and a specified Single object represent the same value.

Equals(Object)

Source:
Single.cs
Source:
Single.cs
Source:
Single.cs

Returns a value indicating whether this instance is equal to a specified object.

public:
 override bool Equals(System::Object ^ obj);
public override bool Equals (object obj);
public override bool Equals (object? obj);
override this.Equals : obj -> bool
Public Overrides Function Equals (obj As Object) As Boolean

Parameters

obj
Object

An object to compare with this instance.

Returns

Boolean

true if obj is an instance of Single and equals the value of this instance; otherwise, false.

Examples

The following code example demonstrates the Equals method.

obj1 = (Single)500;

if ( a.Equals( obj1 ) )
{
   Console::WriteLine( "The value type and reference type values are equal." );
}

obj1 = (Single)500;
if (a.Equals(obj1)) {
    Console.WriteLine("The value type and reference type values are equal.");
}

let obj1 = single 500
if a.Equals obj1 then
    printfn "The value type and reference type values are equal."

Obj1 = CType(500, Single)

If A.Equals(Obj1) Then
    Console.WriteLine("The value type and reference type values are equal.")
End If

Remarks

The Equals method should be used with caution, because two apparently equivalent values can be unequal due to the differing precision of the two values. The following example reports that the Single value .3333 and the Single returned by dividing 1 by 3 are unequal.

// Initialize two floats with apparently identical values
float float1 = .33333f;
object float2 = 1/3;
// Compare them for equality
Console.WriteLine(float1.Equals(float2));    // displays false

// Initialize two floats with apparently identical values
let float1 = 0.33333f
let float2 = box (1f / 3f)
// Compare them for equality
printfn $"{float1.Equals float2}"    // displays false

' Initialize two singles with apparently identical values
Dim single1 As Single = .33333
Dim single2 As Object = 1/3
' Compare them for equality
Console.WriteLine(single1.Equals(single2))    ' displays False

Rather than comparing for equality, one recommended technique involves defining an acceptable margin of difference between two values (such as .01% of one of the values). If the absolute value of the difference between the two values is less than or equal to that margin, the difference is likely to be due to differences in precision and, therefore, the values are likely to be equal. The following example uses this technique to compare .33333 and 1/3, the two Single values that the previous code example found to be unequal.

// Initialize two floats with apparently identical values
float float1 = .33333f;
object float2 = (float) 1/3;
// Define the tolerance for variation in their values
float difference = Math.Abs(float1 * .0001f);

// Compare the values
// The output to the console indicates that the two values are equal
if (Math.Abs(float1 - (float) float2) <= difference)
   Console.WriteLine("float1 and float2 are equal.");
else
   Console.WriteLine("float1 and float2 are unequal.");

// Initialize two floats with apparently identical values
let float1 = 0.33333f
let float2 = box (1f / 3f)
// Define the tolerance for variation in their values
let difference = abs (float1 * 0.0001f)

// Compare the values
// The output to the console indicates that the two values are equal
if abs (float1 - (float2 :?> float32)) <= difference then
    printfn "float1 and float2 are equal."
else
    printfn "float1 and float2 are unequal."

' Initialize two singles with apparently identical values
Dim single1 As Single = .33333
Dim single2 As Object = 1/3
' Define the tolerance for variation in their values
Dim difference As Single = Math.Abs(single1 * .0001f)

' Compare the values
' The output to the console indicates that the two values are equal
If Math.Abs(single1 - CSng(single2)) <= difference Then
   Console.WriteLine("single1 and single2 are equal.")
Else
   Console.WriteLine("single1 and single2 are unequal.")
End If

In this case, the values are equal.

Note

Because Epsilon defines the minimum expression of a positive value whose range is near zero, the margin of difference must be greater than Epsilon. Typically, it is many times greater than Epsilon.

The precision of floating-point numbers beyond the documented precision is specific to the implementation and version of the .NET Framework. Consequently, a comparison of two particular numbers might change between versions of the .NET Framework because the precision of the numbers' internal representation might change.

Notes to Callers

Compiler overload resolution may account for an apparent difference in the behavior of the two Equals(Object) method overloads. If an implicit conversion between the obj argument and a Single is defined and the argument is not typed as an Object, compilers may perform an implicit conversion and call the Equals(Single) method. Otherwise, they call the Equals(Object) method, which always returns false if its obj argument is not a Single value. The following example illustrates the difference in behavior between the two method overloads. In the case of all primitive numeric types except for Double in Visual Basic and except for Decimal and Double in C#, the first comparison returns true because the compiler automatically performs a widening conversion and calls the Equals(Single) method, whereas the second comparison returns false because the compiler calls the Equals(Object) method.

using System;

public class Example
{
   static float value = 112;
   
   public static void Main()
   {
      byte byte1= 112;
      Console.WriteLine("value = byte1: {0,16}", value.Equals(byte1));
      TestObjectForEquality(byte1);

      short short1 = 112;
      Console.WriteLine("value = short1: {0,16}", value.Equals(short1));
      TestObjectForEquality(short1);

      int int1 = 112;
      Console.WriteLine("value = int1: {0,18}", value.Equals(int1));
      TestObjectForEquality(int1);

      long long1 = 112;
      Console.WriteLine("value = long1: {0,17}", value.Equals(long1));
      TestObjectForEquality(long1);
      
      sbyte sbyte1 = 112;
      Console.WriteLine("value = sbyte1: {0,16}", value.Equals(sbyte1));
      TestObjectForEquality(sbyte1);

      ushort ushort1 = 112;
      Console.WriteLine("value = ushort1: {0,16}", value.Equals(ushort1));
      TestObjectForEquality(ushort1);

      uint uint1 = 112;
      Console.WriteLine("value = uint1: {0,18}", value.Equals(uint1));
      TestObjectForEquality(uint1);

      ulong ulong1 = 112;
      Console.WriteLine("value = ulong1: {0,17}", value.Equals(ulong1));
      TestObjectForEquality(ulong1);
      
      decimal dec1 = 112m;
      Console.WriteLine("value = dec1: {0,21}", value.Equals(dec1));
      TestObjectForEquality(dec1);

      double dbl1 = 112;
      Console.WriteLine("value = dbl1: {0,20}", value.Equals(dbl1));
      TestObjectForEquality(dbl1);
   }

   private static void TestObjectForEquality(Object obj)
   {
      Console.WriteLine("{0} ({1}) = {2} ({3}): {4}\n",
                        value, value.GetType().Name,
                        obj, obj.GetType().Name,
                        value.Equals(obj));
   }
}
// The example displays the following output:
//       value = byte1:             True
//       112 (Single) = 112 (Byte): False
//
//       value = short1:             True
//       112 (Single) = 112 (Int16): False
//
//       value = int1:               True
//       112 (Single) = 112 (Int32): False
//
//       value = long1:              True
//       112 (Single) = 112 (Int64): False
//
//       value = sbyte1:             True
//       112 (Single) = 112 (SByte): False
//
//       value = ushort1:             True
//       112 (Single) = 112 (UInt16): False
//
//       value = uint1:               True
//       112 (Single) = 112 (UInt32): False
//
//       value = ulong1:              True
//       112 (Single) = 112 (UInt64): False
//
//       value = dec1:                 False
//       112 (Single) = 112 (Decimal): False
//
//       value = dbl1:                False
//       112 (Single) = 112 (Double): False

let value = 112f

let testObjectForEquality (obj: obj) =
    printfn $"{value} ({value.GetType().Name}) = {obj} ({obj.GetType().Name}): {value.Equals obj}\n"

[<EntryPoint>]
let main _ =
    let byte1= 112uy
    printfn $"value = byte1: {value.Equals byte1,16}"
    testObjectForEquality byte1

    let short1 = 112s
    printfn $"value = short1: {value.Equals short1,16}"
    testObjectForEquality short1

    let int1 = 112
    printfn $"value = int1: {value.Equals int1,18}"
    testObjectForEquality int1

    let long1 = 112L
    printfn $"value = long1: {value.Equals long1,17}"
    testObjectForEquality long1
    
    let sbyte1 = 112y
    printfn $"value = sbyte1: {value.Equals sbyte1,16}"
    testObjectForEquality sbyte1

    let ushort1 = 112us
    printfn $"value = ushort1: {value.Equals ushort1,16}"
    testObjectForEquality ushort1

    let uint1 = 112u
    printfn $"value = uint1: {value.Equals uint1,18}"
    testObjectForEquality uint1

    let ulong1 = 112uL
    printfn $"value = ulong1: {value.Equals ulong1,17}"
    testObjectForEquality ulong1
    
    let dec1 = 112m
    printfn $"value = dec1: {value.Equals dec1,21}"
    testObjectForEquality dec1

    let dbl1 = 112.
    printfn $"value = dbl1: {value.Equals dbl1,20}"
    testObjectForEquality dbl1
    0

// The example displays the following output:
//       value = byte1:             True
//       112 (Single) = 112 (Byte): False
//
//       value = short1:             True
//       112 (Single) = 112 (Int16): False
//
//       value = int1:               True
//       112 (Single) = 112 (Int32): False
//
//       value = long1:              True
//       112 (Single) = 112 (Int64): False
//
//       value = sbyte1:             True
//       112 (Single) = 112 (SByte): False
//
//       value = ushort1:             True
//       112 (Single) = 112 (UInt16): False
//
//       value = uint1:               True
//       112 (Single) = 112 (UInt32): False
//
//       value = ulong1:              True
//       112 (Single) = 112 (UInt64): False
//
//       value = dec1:                 False
//       112 (Single) = 112 (Decimal): False
//
//       value = dbl1:                False
//       112 (Single) = 112 (Double): False

Module Example
   Dim value As Single = 112
   
   Public Sub Main()
      Dim byte1 As Byte = 112
      Console.WriteLine("value = byte1: {0,16}", value.Equals(byte1))
      TestObjectForEquality(byte1)
      
      Dim short1 As Short = 112
      Console.WriteLine("value = short1: {0,16}", value.Equals(short1))
      TestObjectForEquality(short1)

      Dim int1 As Integer = 112
      Console.WriteLine("value = int1: {0,18}", value.Equals(int1))
      TestObjectForEquality(int1)

      Dim long1 As Long = 112
      Console.WriteLine("value = long1: {0,17}", value.Equals(long1))
      TestObjectForEquality(long1)

      Dim sbyte1 As SByte = 112
      Console.WriteLine("value = sbyte1: {0,16}", value.Equals(sbyte1))
      TestObjectForEquality(sbyte1)
      
      Dim ushort1 As UShort = 112
      Console.WriteLine("value = ushort1: {0,16}", value.Equals(ushort1))
      TestObjectForEquality(ushort1)

      Dim uint1 As UInteger = 112
      Console.WriteLine("value = uint1: {0,18}", value.Equals(uint1))
      TestObjectForEquality(uint1)

      Dim ulong1 As ULong = 112
      Console.WriteLine("value = ulong1: {0,17}", value.Equals(ulong1))
      TestObjectForEquality(ulong1)
      
      Dim dec1 As Decimal = 112d
      Console.WriteLine("value = dec1: {0,20}", value.Equals(dec1))
      TestObjectForEquality(dec1)

      Dim dbl1 As Double = 112
      Console.WriteLine("value = dbl1: {0,20}", value.Equals(dbl1))
      TestObjectForEquality(dbl1)
   End Sub
   
   Private Sub TestObjectForEquality(obj As Object)
      Console.WriteLine("{0} ({1}) = {2} ({3}): {4}",
                        value, value.GetType().Name,
                        obj, obj.GetType().Name,
                        value.Equals(obj))
      Console.WriteLine()
   End Sub
End Module
' The example displays the following output:
'       value = byte1:             True
'       112 (Single) = 112 (Byte): False
'
'       value = short1:             True
'       112 (Single) = 112 (Int16): False
'
'       value = int1:               True
'       112 (Single) = 112 (Int32): False
'
'       value = long1:              True
'       112 (Single) = 112 (Int64): False
'
'       value = sbyte1:             True
'       112 (Single) = 112 (SByte): False
'
'       value = ushort1:             True
'       112 (Single) = 112 (UInt16): False
'
'       value = uint1:               True
'       112 (Single) = 112 (UInt32): False
'
'       value = ulong1:              True
'       112 (Single) = 112 (UInt64): False
'
'       value = dec1:                 True
'       112 (Single) = 112 (Decimal): False
'
'       value = dbl1:                False
'       112 (Single) = 112 (Double): False

See also

Applies to

Equals(Single)

Source:
Single.cs
Source:
Single.cs
Source:
Single.cs

Returns a value indicating whether this instance and a specified Single object represent the same value.

public:
 virtual bool Equals(float obj);
public bool Equals (float obj);
override this.Equals : single -> bool
Public Function Equals (obj As Single) As Boolean

Parameters

obj
Single

An object to compare with this instance.

Returns

Boolean

true if obj is equal to this instance; otherwise, false.

Implements

Equals(T)

Remarks

For more information about this API, see Supplemental API remarks for Single.Equals.

Notes to Callers

Compiler overload resolution may account for an apparent difference in the behavior of the two Equals(Object) method overloads. If an implicit conversion between the obj argument and a Single is defined and the argument is not typed as an Object, compilers may perform an implicit conversion and call the Equals(Single) method. Otherwise, they call the Equals(Object) method, which always returns false if its obj argument is not a Single value. The following example illustrates the difference in behavior between the two method overloads. In the case of all primitive numeric types except for Double in Visual Basic and except for Decimal and Double in C#, the first comparison returns true because the compiler automatically performs a widening conversion and calls the Equals(Single) method, whereas the second comparison returns false because the compiler calls the Equals(Object) method.

using System;

public class Example
{
   static float value = 112;
   
   public static void Main()
   {
      byte byte1= 112;
      Console.WriteLine("value = byte1: {0,16}", value.Equals(byte1));
      TestObjectForEquality(byte1);

      short short1 = 112;
      Console.WriteLine("value = short1: {0,16}", value.Equals(short1));
      TestObjectForEquality(short1);

      int int1 = 112;
      Console.WriteLine("value = int1: {0,18}", value.Equals(int1));
      TestObjectForEquality(int1);

      long long1 = 112;
      Console.WriteLine("value = long1: {0,17}", value.Equals(long1));
      TestObjectForEquality(long1);
      
      sbyte sbyte1 = 112;
      Console.WriteLine("value = sbyte1: {0,16}", value.Equals(sbyte1));
      TestObjectForEquality(sbyte1);

      ushort ushort1 = 112;
      Console.WriteLine("value = ushort1: {0,16}", value.Equals(ushort1));
      TestObjectForEquality(ushort1);

      uint uint1 = 112;
      Console.WriteLine("value = uint1: {0,18}", value.Equals(uint1));
      TestObjectForEquality(uint1);

      ulong ulong1 = 112;
      Console.WriteLine("value = ulong1: {0,17}", value.Equals(ulong1));
      TestObjectForEquality(ulong1);
      
      decimal dec1 = 112m;
      Console.WriteLine("value = dec1: {0,21}", value.Equals(dec1));
      TestObjectForEquality(dec1);

      double dbl1 = 112;
      Console.WriteLine("value = dbl1: {0,20}", value.Equals(dbl1));
      TestObjectForEquality(dbl1);
   }

   private static void TestObjectForEquality(Object obj)
   {
      Console.WriteLine("{0} ({1}) = {2} ({3}): {4}\n",
                        value, value.GetType().Name,
                        obj, obj.GetType().Name,
                        value.Equals(obj));
   }
}
// The example displays the following output:
//       value = byte1:             True
//       112 (Single) = 112 (Byte): False
//
//       value = short1:             True
//       112 (Single) = 112 (Int16): False
//
//       value = int1:               True
//       112 (Single) = 112 (Int32): False
//
//       value = long1:              True
//       112 (Single) = 112 (Int64): False
//
//       value = sbyte1:             True
//       112 (Single) = 112 (SByte): False
//
//       value = ushort1:             True
//       112 (Single) = 112 (UInt16): False
//
//       value = uint1:               True
//       112 (Single) = 112 (UInt32): False
//
//       value = ulong1:              True
//       112 (Single) = 112 (UInt64): False
//
//       value = dec1:                 False
//       112 (Single) = 112 (Decimal): False
//
//       value = dbl1:                False
//       112 (Single) = 112 (Double): False

let value = 112f

let testObjectForEquality (obj: obj) =
    printfn $"{value} ({value.GetType().Name}) = {obj} ({obj.GetType().Name}): {value.Equals obj}\n"

[<EntryPoint>]
let main _ =
    let byte1= 112uy
    printfn $"value = byte1: {value.Equals byte1,16}"
    testObjectForEquality byte1

    let short1 = 112s
    printfn $"value = short1: {value.Equals short1,16}"
    testObjectForEquality short1

    let int1 = 112
    printfn $"value = int1: {value.Equals int1,18}"
    testObjectForEquality int1

    let long1 = 112L
    printfn $"value = long1: {value.Equals long1,17}"
    testObjectForEquality long1
    
    let sbyte1 = 112y
    printfn $"value = sbyte1: {value.Equals sbyte1,16}"
    testObjectForEquality sbyte1

    let ushort1 = 112us
    printfn $"value = ushort1: {value.Equals ushort1,16}"
    testObjectForEquality ushort1

    let uint1 = 112u
    printfn $"value = uint1: {value.Equals uint1,18}"
    testObjectForEquality uint1

    let ulong1 = 112uL
    printfn $"value = ulong1: {value.Equals ulong1,17}"
    testObjectForEquality ulong1
    
    let dec1 = 112m
    printfn $"value = dec1: {value.Equals dec1,21}"
    testObjectForEquality dec1

    let dbl1 = 112.
    printfn $"value = dbl1: {value.Equals dbl1,20}"
    testObjectForEquality dbl1
    0

// The example displays the following output:
//       value = byte1:             True
//       112 (Single) = 112 (Byte): False
//
//       value = short1:             True
//       112 (Single) = 112 (Int16): False
//
//       value = int1:               True
//       112 (Single) = 112 (Int32): False
//
//       value = long1:              True
//       112 (Single) = 112 (Int64): False
//
//       value = sbyte1:             True
//       112 (Single) = 112 (SByte): False
//
//       value = ushort1:             True
//       112 (Single) = 112 (UInt16): False
//
//       value = uint1:               True
//       112 (Single) = 112 (UInt32): False
//
//       value = ulong1:              True
//       112 (Single) = 112 (UInt64): False
//
//       value = dec1:                 False
//       112 (Single) = 112 (Decimal): False
//
//       value = dbl1:                False
//       112 (Single) = 112 (Double): False

Module Example
   Dim value As Single = 112
   
   Public Sub Main()
      Dim byte1 As Byte = 112
      Console.WriteLine("value = byte1: {0,16}", value.Equals(byte1))
      TestObjectForEquality(byte1)
      
      Dim short1 As Short = 112
      Console.WriteLine("value = short1: {0,16}", value.Equals(short1))
      TestObjectForEquality(short1)

      Dim int1 As Integer = 112
      Console.WriteLine("value = int1: {0,18}", value.Equals(int1))
      TestObjectForEquality(int1)

      Dim long1 As Long = 112
      Console.WriteLine("value = long1: {0,17}", value.Equals(long1))
      TestObjectForEquality(long1)

      Dim sbyte1 As SByte = 112
      Console.WriteLine("value = sbyte1: {0,16}", value.Equals(sbyte1))
      TestObjectForEquality(sbyte1)
      
      Dim ushort1 As UShort = 112
      Console.WriteLine("value = ushort1: {0,16}", value.Equals(ushort1))
      TestObjectForEquality(ushort1)

      Dim uint1 As UInteger = 112
      Console.WriteLine("value = uint1: {0,18}", value.Equals(uint1))
      TestObjectForEquality(uint1)

      Dim ulong1 As ULong = 112
      Console.WriteLine("value = ulong1: {0,17}", value.Equals(ulong1))
      TestObjectForEquality(ulong1)
      
      Dim dec1 As Decimal = 112d
      Console.WriteLine("value = dec1: {0,20}", value.Equals(dec1))
      TestObjectForEquality(dec1)

      Dim dbl1 As Double = 112
      Console.WriteLine("value = dbl1: {0,20}", value.Equals(dbl1))
      TestObjectForEquality(dbl1)
   End Sub
   
   Private Sub TestObjectForEquality(obj As Object)
      Console.WriteLine("{0} ({1}) = {2} ({3}): {4}",
                        value, value.GetType().Name,
                        obj, obj.GetType().Name,
                        value.Equals(obj))
      Console.WriteLine()
   End Sub
End Module
' The example displays the following output:
'       value = byte1:             True
'       112 (Single) = 112 (Byte): False
'
'       value = short1:             True
'       112 (Single) = 112 (Int16): False
'
'       value = int1:               True
'       112 (Single) = 112 (Int32): False
'
'       value = long1:              True
'       112 (Single) = 112 (Int64): False
'
'       value = sbyte1:             True
'       112 (Single) = 112 (SByte): False
'
'       value = ushort1:             True
'       112 (Single) = 112 (UInt16): False
'
'       value = uint1:               True
'       112 (Single) = 112 (UInt32): False
'
'       value = ulong1:              True
'       112 (Single) = 112 (UInt64): False
'
'       value = dec1:                 True
'       112 (Single) = 112 (Decimal): False
'
'       value = dbl1:                False
'       112 (Single) = 112 (Double): False

See also

Applies to