equality

I have the following C# code (from a library I'm using) that tries to find a certificate comparing the thumbprint. Notice that in the following code both mycert.Thumbprint and certificateThumbprint are strings. var certificateThumbprint = AppSettings.CertificateThumbprint; var cert = myStore.Certificates.OfType<X509Certificate2>().FirstOrDefault( mycert => mycert.Thumbprint != null && mycert.Thumbprint.Equals(certificateThumbprint) ); This fails to find the certificate with the thumbprint because mycert.Thumbprint.Equals(certificateThumbprint) is false even when the strings are equal. mycert

scala> List(1,2,3) == List(1,2,3) res2: Boolean = true scala> Map(1 -> "Olle") == Map(1 -> "Olle") res3: Boolean = true But when trying to do the same with Array, it does not work the same. Why? scala> Array('a','b') == Array('a','b') res4: Boolean = false I have used 2.8.0.RC7 and 2.8.0.Beta1-prerelease. Because the definition of "equals" for Arrays is that they refer to the same array. This is consistent with Java's array equality, using Object.Equals , so it compares references. If you want to check pairwise elements, then use sameElements Array('a','b').sameElements(Array('a','b')) or

How do you handle object equality for java objects managed by hibernate? In the 'hibernate in action' book they say that one should favor business keys over surrogate keys. Most of the time, i do not have a business key. Think of addresses mapped to a person. The addresses are keeped in a Set and displayed in a Wicket RefreshingView (with a ReuseIfEquals strategy). I could either use the surrogate id or use all fields in the equals() and hashCode() functions. The problem is that those fields change during the lifetime ob the object. Either because the user entered some data or the id changes

What's your approach on writing equality checks for the structs and classes you create? 1) Does the "full" equality checking require that much of boilerplate code (like override Equals , override GetHashCode , generic Equals , operator== , operator!= )? 2) Do you specify explicitly that your classes model the IEquatable<T> interface? 3) Do I understand correctly, that there is no actual way to automatically apply Equals overrides, when I invoke something like a == b and I always have to implement both the Equals and operator== members? You're right, this is a lot of boiler-plate code, and you

In Firefox 3.5, I type this in the Firebug console : false=={} // => evals to false {}==false // syntax error What is the explanation for this ? bobince { at the start of a statement signals a ‘statement block’ (see ECMA-262-3 section 12.1), which contains a list of statements. } immediately ends the statement block with no statements in it. That's fine. But now the parser is looking for the next statement: ==false Huh? That's not a statement; syntax error. What are statement blocks for? Well, you are writing a statement block every time you say: if (something) { ... } JavaScript defines these

I've got a class A , which conforms to Equatable protocol and implements == function. In subclass B I override == with more checks. However, when I do comparison between two arrays of instances of B (which both have type Array<A> ), == for A is invoked. Of course if I change type of both arrays to Array<B> , == for B is invoked. I came up with the following solution: A.swift: internal func ==(lhs: A, rhs: A) -> Bool { if lhs is B && rhs is B { return lhs as! B == rhs as! B } return ... } Which looks really ugly and must be extended for every subclass of A . Is there a way to make sure that ==