equality

问题 I need to find out if two dates the user selects are the same in Javascript. The dates are passed to this function in a String ("xx/xx/xxxx").That is all the granularity I need. Here is my code: var valid = true; var d1 = new Date($('#datein').val()); var d2 = new Date($('#dateout').val()); alert(d1+"\n"+d2); if(d1 > d2) { alert("Your check out date must be after your check in date."); valid = false; } else if(d1 == d2) { alert("You cannot check out on the same day you check in."); valid =

问题 I've just noticed that Array doesn't override the triple equal sign method === , which is sometimes called the case equality method. x = 2 case x when [1, 2, 3] then "match" else "no match" end # => "no match" whereas the range operator does: x = 2 case x when 1..3 then "match" else "no match" end # => "match" You can do a workaround for arrays, however: x = 2 case x when *[1, 2, 3] then "match" else "no match" end # => "match" Is it known why this is the case? Is it because it's more likely

问题 While nan == nan is always False , in many cases people want to treat them as equal, and this is enshrined in pandas.DataFrame.equals: NaNs in the same location are considered equal. Of course, I can write def equalp(x, y): return (x == y) or (math.isnan(x) and math.isnan(y)) However, this will fail on containers like [float("nan")] and isnan barfs on non-numbers (so the complexity increases). So, what do people do to compare complex Python objects which may contain nan ? PS . Motivation:

问题 This question already has answers here : How to determine equality for two JavaScript objects? (60 answers) Closed 3 years ago . I'm creating a lib on vectors in typescript. My very first test failed:). It's related to object equality in TypeScript/JavaScript but I can't find a way to make the test green. No object equality is mentioned in typescript's official doc http://www.typescriptlang.org/Handbook#classes. Could someone please give me a hand ? This is the source code. class Vector { x:

问题 I have the Situation that I have an object which I want to check for equality with another object . public static bool Equals(object a, object b) { return a.Equals(b); } A Problem occurs when a = 1 (integer) and b = 1 (ushort (or basically not integer)) . I wondered whether this shouldn't yield true, but it does return false... Edit What makes it even worse is this: Hashtable ht = new Hashtable(); ht.Add((int)1, "SOME STRING"); ht.Add((short)1, "SOME STRING"); ht.Add((long)1, "SOME STRING");

问题 According to the Python docs: "when defining __eq__() , one should also define __ne__() so that the operators will behave as expected". However, it appears that Python computes __ne__ as not __eq__ automatically: In [8]: class Test: def __eq__(self, other): print("calling __eq__") ...: return isinstance(other, Test) ...: In [9]: a = Test() In [10]: b = Test() In [11]: a == b calling __eq__ Out[11]: True In [12]: a != b calling __eq__ Out[12]: False In [13]: a == 1 calling __eq__ Out[13]:

问题 Suppose I have the following clojure functions: (defn a [x] (* x x)) (def b (fn [x] (* x x))) (def c (eval (read-string "(defn d [x] (* x x))"))) Is there a way to test for the equality of the function expression - some equivalent of (eqls a b) returns true? 回答1: I agree with the above answers in regards to Clojure not having a built in ability to determine the equivalence of two functions and that it has been proven that you can not test programs functionally (also known as black box testing

问题 I already posted a question about function equality. It quickly concluded that general function equality is an incredibly hard problem and might be mathematically disprovable. I would like to stub up a function function equal(f, g, domain) { } f & g are halting functions that take one argument. Their argument is an natural number. These functions will return a boolean. If no domain is passed then you may assume the domain defaults to all natural numbers. The structure of domain is whatever is

问题 I am currently working on comparing two complex objects of the same type, with multiple fields consisting of data structures of custom object types. Assuming that none of the custom objects has overriden the hashCode() method, if I compare the hashcodes of every field in the objects, and they will turn out to be the same, do I have a 100% confidence that the content of the compared objects is the same? If not, which method would you recommend to compare two objects, assuming I can't use any

问题 If I have three or more objects like so: a = 4 b = 4 c = 4 d = 2 what would be a clean ruby-style way of determining whether they are all equal? Any bespoke methods for running equality tests on three or more elements? I suppose I could do something like this: arrays = [a,b,c,d].map{|x| [x]} arrays.first == arrays.reduce(:&) ? true : false which appears to work, but feels sort of ham handed, and might be difficult for other developers to read. 回答1: [a,b,c,d].any?{|x| x != a} or array.any?{|x|