Why does new String(‘hello’) === new String(‘hello’) evaluate to False? [duplicate]

Two String objects will always be unequal to each other. Note that JavaScript has string primitive values as well as a String constructor to create wrapper objects. All object equality comparisons (especially with ===) are carried out as a test for reference equality. References to two different objects will of course never be equal to …

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Why is operator!= removed in C++20 for many standard library types?

In C++20 the way that the relational operators work was changed, notably with the introduction of the spaceship <=> operator. In particular, If you only provide operator==, then a != b is rewritten to !(a == b). From [over.match.oper]/3.4: The rewritten candidate set is determined as follows: For the relational ([expr.rel]) operators, the rewritten candidates …

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Why is operator!= removed in C++20 for many standard library types?

In C++20 the way that the relational operators work was changed, notably with the introduction of the spaceship <=> operator. In particular, If you only provide operator==, then a != b is rewritten to !(a == b). From [over.match.oper]/3.4: The rewritten candidate set is determined as follows: For the relational ([expr.rel]) operators, the rewritten candidates …

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Comparing numpy arrays containing NaN

For versions of numpy prior to 1.19, this is probably the best approach in situations that don’t specifically involve unit tests: >>> ((a == b) | (numpy.isnan(a) & numpy.isnan(b))).all() True However, modern versions provide the array_equal function with a new keyword argument, equal_nan, which fits the bill exactly. This was first pointed out by flyingdutchman; …

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Difference between == and === in JavaScript [duplicate]

Take a look here: http://longgoldenears.blogspot.com/2007/09/triple-equals-in-javascript.html The 3 equal signs mean “equality without type coercion”. Using the triple equals, the values must be equal in type as well. 0 == false // true 0 === false // false, because they are of a different type 1 == “1” // true, automatic type conversion for value only …

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Which equals operator (== vs ===) should be used in JavaScript comparisons?

The strict equality operator (===) behaves identically to the abstract equality operator (==) except no type conversion is done, and the types must be the same to be considered equal. Reference: Javascript Tutorial: Comparison Operators The == operator will compare for equality after doing any necessary type conversions. The === operator will not do the …

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