Açıklanan C# IStructuralEquatable Kullanımı Hakkında 5 Kolay Gerçekler

Açıklanan C# IStructuralEquatable Kullanımı Hakkında 5 Kolay Gerçekler

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It's normally expected that if you implement IEquatable.Equals you will also override Object.Equals to be consistent. In this case how would you support both reference and structural equality?

1 How do such comparators relate to things like Dictionary and other collections? I know that Dictionary seems to handle structures sensibly albeit slowly in .

. The best example of this is arrays, which with .Safi 4 now implement the IStructuralEquatable interface. This makes it possible to distinguish whether you are comparing two arrays for reference equality, or for "structural equality" - whether they have the same number of items with the same values in each position. Here's an example:

Does anyone know what happens if you do not implement iequtalable when using generic collections? 2

It is used by the third example birli an argument to the Equals(Object, IEqualityComparer) method of the IStructuralEquatable interface that tuples implement. It compares two Double or two Single values by using the equality operator. It passes values of any other type to the default equality comparer.

– Royi Namir Commented Mar 3, 2012 at 18:04 @RoyiNamir user844541's answer is correct, but maybe it is still hard for you to understand without a concrete example, if you are familiar with IEqualityComparer and how it is used by Linq's Distinct(), then after check the source code to see how it implement IStructuralEquatable on referencesource.microsoft.com/#mscorlib/system/collections/…, then you will see how it work.

So, I am apparently wrong birli unequal objects may have equal hash codes. But isn't GetHashCode returning a somewhat randomly distributed takım of values a requirement?

I've noticed these two interfaces, and several associated classes, have been added in .Safi 4. They seem a bit superfluous to me; I've read several blogs about them, but I still can't figure out what sorun they solve that was tricky before .Kupkuru 4.

Reading through C# IStructuralEquatable nerelerde kullanılıyor the excellent blog post by Sergey on struct equality performance he mentions that the default implementations are pretty slow and using boxing for each member. Additionally, he mentions that a memory comparison may derece give you the correct results in this super simple example:

Task oluşturmanın hizmetlemci üzerinde maliyeti vardır ve çok kısaca devam eden işlemlemler muhtevain bir task yapılandırmak genel anlamda elan yavaş çhileışan uygulamalara saik evet.

Kupkuru on a certain ortam, I'm compelled to issue the standard warning not to rely on the values of hashcodes or how they are computed, since it is hamiş guaranteed to be the same across updates or platforms.

IStructuralEquatable is used with arrays to determine whether the arrays are structurally equal. The StructuralEqualityComparer.Equals method is used for this purpose.

Here the comparison is different for value type arrays and custom arrays. In .Safi 4.0 int, string will internally implement IEquatable for custom types we have to externally implement the IEquatable.

3 feature called Tuple Equality! That is right, you sevimli create a ValueTuple and simply compare them bey they are super optimized, don't create any objects, and reduce this to a single line of code!