equality

问题 I'm having trouble understanding whether it is possible to prove that two sets (in this case regular languages) are identical and thus interchangeable. From what I understand, sets can be equivalent even if they are not constructively equal. Regular languages are sets of strings, but I don't see how to say that r1 = r2 so that something like symmetry can be used in a proof. Here is my RegularLanguage declaration: Inductive RegularLanguage (A : Set) : Set := | EmptyLang : RegularLanguage A |

问题 This question is close, but still not what I want. I'd like to assert in a generic way that two bean objects are equivalent. In case they are not, I'd like a detailed error message explaining the difference instead of a boolean "equal" or "not equal". 回答1: I recommend you use unitils library: http://www.unitils.org/tutorial-reflectionassert.html public class User { private long id; private String first; private String last; public User(long id, String first, String last) { this.id = id; this

问题 I think this is the question, anyway. I am using a RelayCommand, which decorates an ICommand with two delegates. One is Predicate for the _canExecute and the other is Action for the _execute method. ---Background motivation -- The motivation has to do with unit testing ViewModels for a WPF presentation. A frequent pattern is that I have one ViewModel that has an ObservableCollection, and I want a unit test to prove the data in that collection is what I expect given some source data (which

问题 This question already has answers here : how to determine if 2 dates object equals each other? [duplicate] (3 answers) Closed 2 years ago . I have been messing around with JSFiddle to solve this problem in FreeCodeCamp. When I use Date as a string (i.e., no "new"): Case 1: function isSameDay (dtFrom, dtTo) { return dtFrom == dtTo } let today = Date() let tomorrow = Date() console.log(today) console.log(tomorrow) console.log(isSameDay(today, tomorrow)) isSameDay returns true . However when I

问题 Why won't this compile? fn isPalindrome<T>(v: Vec<T>) -> bool { return v.reverse() == v; } I get error[E0308]: mismatched types --> src/main.rs:2:25 | 2 | return v.reverse() == v; | ^ expected (), found struct `std::vec::Vec` | = note: expected type `()` found type `std::vec::Vec<T>` 回答1: Read up on the documentation for the function you are using: Reverse the order of elements in a slice, in place. Or check the function signature: fn reverse(&mut self) The return value of the method is the

问题 I need to compare two datetime values to determine equality(exactly the same),using minute precision.Would this be the best way to do it? My dates could have seconds and milliseconds, but i want to consider only down till minutes. where (Math.Abs(datetime1.Subtract(datetime2).TotalMinutes) == 0) 回答1: Checking whether Math.Abs(diff.TotalMinutes) == 0 won't do it, no - that's checking whether they're exactly the same. Are you trying to check whether they have the same minute, or whether they're

问题 I'm trying to develop a project in Groovy and I've found some of my tests failing in an odd way: I have an interface Version extends Comparable<Version> with two concrete subclasses. Both override equals(Object) and compareTo(Version) - however, if I try to compare two instances of Version that are of different concrete types using == , the equality check fails even though explicit equals and compareTo checks pass. If I remove the extends Comparable<Version> part of Version , I get the

问题 I do have a simialar problem like descripted here. But with two differences first I do use the stream api and second I do have an equals() and hashCode() method already. But within the stream the equalitity of the of Blogs are in this context not the same as defined in the Blog class. Collection<Blog> elements = x.stream() ... // a lot of filter and map stuff .peek(p -> sysout(p)) // a stream of Blog .? // how to remove duplicates - .distinct() doesn't work I do have a class with an equal

问题 Consider this snippet: class SomeClass(object): def __init__(self, someattribute="somevalue"): self.someattribute = someattribute def __eq__(self, other): return self.someattribute == other.someattribute def __ne__(self, other): return not self.__eq__(other) list_of_objects = [SomeClass()] print(SomeClass() in list_of_objects) set_of_objects = set([SomeClass()]) print(SomeClass() in set_of_objects) which evaluates to: True False Can anyone explain why the 'in' keyword has a different meaning

问题 In C#, how can we check reference equality for a type that implements equality operator? class C { public int Val{get;set;} public static bool operator ==(C c1, C c2) { return c1.Val == c2.Val; } public static bool operator !=(C c1, C c2) { return c1.Val != c2.Val; } } class Program { public static void Main(string[] args) { C c1=new C(){Val=1}; C c2=new C(){Val=1}; Console.WriteLine(c1==c2);//True. but they are not same objects. //How can I Check that? Console.Write("Press any key to