equality-operator Questions

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In rust, is there a version of f32 / f64 that implements Eq? The only reason I can see for f32 / f64 not implementing Eq is that NaN != NaN. Potential ways such a type could behave: The type could...
Chon asked 18/8, 2022 at 20:50

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I have a struct that's defined like this: struct Vec3 { float x, y, z; }; When I attempted to use std::unique on a std::vector<Vec3>, I was met with this error: Description Resource ...

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Precondition: Consider such a class or struct T, that for two objects a and b of type T memcmp(&a, &b, sizeof(T)) == 0 yields the same result as a.member1 == b.member1 && a.memb...

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Note: it has been suggested that this question duplicates Can I compare int with size_t directly in C?, but the question here specifically asks about comparing size_t with a negative value. F...
Siegel asked 17/4, 2023 at 13:6

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What is the difference between the comparison operators == and === in Kotlin? class A { var foo = 1 } var a1 = A() var a2 = A() println(a1 == a2) // output false println(a1 === a2) // output f...
Gas asked 14/7, 2018 at 14:58

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My application needs to compare Series instances that sometimes contain nans. That causes ordinary comparison using == to fail, since nan != nan: import numpy as np from pandas import Series s1 = ...
Underside asked 26/8, 2013 at 21:37

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For my unittest, I want to check if two arrays are identical. Reduced example: a = np.array([1, 2, np.NaN]) b = np.array([1, 2, np.NaN]) if np.all(a==b): print 'arrays are equal' This does not w...
Erelia asked 22/5, 2012 at 21:18

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According to cppreference, std::type_info::operator!= gets removed with C++20, however, std::type_info::operator== apparently remains. What's the reasoning behind? I might agree on comparing for i...
Vudimir asked 10/10, 2019 at 9:39

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string s; bool b[] = {s=="", s==s.c_str(), s.c_str()==""}; sets b[] = {true, true, false}; why is b[2] false? If A==B and A==C, should that not imply B==C?
Irrawaddy asked 17/10, 2019 at 16:55

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I'm using JSLint to go through JavaScript, and it's returning many suggestions to replace == (two equals signs) with === (three equals signs) when doing things like comparing idSele_UNVEHtype...

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Why is [] !== [] in JavaScript? I read through https://developer.mozilla.org/en-US/docs/Web/JavaScript/Equality_comparisons_and_sameness but I could not find anything that explains this. Ed...
Unkindly asked 28/10, 2016 at 21:10

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A few weeks ago, I have read this thread Is < faster than <=? about comparison operators in C. It was said that there is no difference in the performance between < and <= as they are in...

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I'm learning about operator overloading in C++, and I see that == and != are simply some special functions which can be customized for user-defined types. My concern is, though, why are there two s...
Slowly asked 13/6, 2016 at 22:14

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I'm curious to know why null == undefined returns true but null >= undefined returns false Is the inclusion of the greater than operator coercing the values differently?
Tymothy asked 3/12, 2015 at 0:38

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Why does {} == false evaluate to false while [] == false evaluates to true in javascript?
Sheetfed asked 16/1, 2015 at 17:16

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Why does the following statement return false in JavaScript? new String('hello') === new String('hello')

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I am developing an application in Android using Eclipse. I wrote the following code and in tests the first and third "if" block is not reachable. Why? When I add a leading zero to a number, the eq...
Magnesite asked 5/5, 2012 at 11:40

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In a question regarding the use of typeid is C++, I suggested it could be used to compare types in objects comparison. I haven't seen it done much, but I had Java's equals in mind. Looking into Ja...
Viewing asked 20/7, 2011 at 19:33

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Possible Duplicates: Difference between == and === in JavaScript Javascript === vs == : Does it matter which “equal” operator I use? What's the difference between == and ...

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int main (int argc, **argv) { if (argv[1] == "-hello") printf("True\n"); else printf("False\n"); } # ./myProg -hello False Why? I realize strcmp(argv[1], "-hello") == 0 returns true....
Actinomycete asked 14/10, 2010 at 13:27

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What is the difference between == and === in JavaScript? I have also seen != and !== operators. Are there more such operators?
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