C#•2y ago

✅ EqualityComparer

Hello, anyone know of this code work ? --> EqualityComparer<ICollection<myclass>> .Default.Equals(myclassS, x.myclassS) cause i'm wondering if this will trigger the equals override inside myclass to compare each element or if it will do an equal on the collection to look if they have the same hashcode or something like that

6 Replies

MODiX•2y ago

thinker227#5176

REPL Result: Success

class MyClass
{
    public override bool Equals(object? other)
    {
        Console.WriteLine("equals");
        return other is MyClass;
    } 
}

List<MyClass> a = new() { new() };
List<MyClass> b = new() { new() };
EqualityComparer<ICollection<MyClass>>.Default.Equals(a, b)

class MyClass
{
    public override bool Equals(object? other)
    {
        Console.WriteLine("equals");
        return other is MyClass;
    } 
}

List<MyClass> a = new() { new() };
List<MyClass> b = new() { new() };
EqualityComparer<ICollection<MyClass>>.Default.Equals(a, b)

Result: bool

False

False

Compile: 774.298ms | Execution: 95.486ms | React with ❌ to remove this embed.

Thinker•2y ago

It calls List<T>.Equals (in this case) EqualityComparer<T> doesn't do anything special for collections

ElioOP•2y ago

So if i want to compare 2 list i should make my own method or can i override the equals methods without creating my own List class ?

Thinker•2y ago

You can use SequenceEqual from Linq

MODiX•2y ago

thinker227#5176

REPL Result: Success

new[] { 1, 2, 3 }.SequenceEqual(new[] { 1, 2, 3 })

new[] { 1, 2, 3 }.SequenceEqual(new[] { 1, 2, 3 })

Result: bool

True

True

Compile: 456.640ms | Execution: 48.174ms | React with ❌ to remove this embed.

ElioOP•2y ago

😮 i will try right away thanks !

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✅ EqualityComparer