Why does the “is” keyword have a different behavior when there is a dot in the string?

is verifies object identity, and any implementation of Python, when it meets literal of immutable types, is perfectly free to either make a new object of that immutable type, or seek through existing objects of that type to see if some of them could be reused (by adding a new reference to the same underlying … Read more

Sets, Functors and Eq confusion

Another argument against Set being a Functor – it is widely accepted that being a Functor allows you to transform the “elements” of a “collection” while preserving the shape. […] Clearly, any functor instance for Set has the possibility to change the shape, by reducing the number of elements in the set. I’m afraid that … Read more

What problem does IStructuralEquatable and IStructuralComparable solve?

All types in .NET support the Object.Equals() method which, by default, compares two types for reference equality. However, sometimes, it also desirable to be able to compare two types for structural equality. The best example of this is arrays, which with .NET 4 now implement the IStructuralEquatable interface. This makes it possible to distinguish whether … Read more

Comparing arrays for equality in C++

if (iar1 == iar2) Here iar1 and iar2 are decaying to pointers to the first elements of the respective arrays. Since they are two distinct arrays, the pointer values are, of course, different and your comparison tests not equal. To do an element-wise comparison, you must either write a loop; or use std::array instead std::array<int, … Read more

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