equals

问题 i am very very new to Java and i would like to know how can i compare 2 integers? I know == gets the job done.. but what about equals? Can this compare 2 integers? (when i say integers i mean "int" not "Integer"). My code is: import java.lang.*; import java.util.Scanner; //i read 2 integers the first_int and second_int //Code above if(first_int.equals(second_int)){ //do smth } //Other Code but for some reason this does not work.. i mean the Netbeans gives me an error: "int cannot be

问题 In java, when you are testing what the object's class is equal to would you use .equals() or == For example in the code below would it be: if(object.getClass() == MyClass.class) or if(object.getClass().equals(MyClass.class)) 回答1: You can use instanceof for that kind of comparision too, anyway, The Class implementation don´t override equals so comparing using == is correct, it will check the runtime class, f.e: this code will shows true: public static void main(String[] args) { Object object =

问题 I'd like my EqualTester generic class to call the overridden equals(...) method of its generic parameter, but it seems to call Object.equals instead. Here is my test code: import junit.framework.TestCase; public class EqualityInsideGenerics extends TestCase { public static class EqualTester<V> { public boolean check(V v1, V v2) { return v1.equals(v2); } } public static class K { private int i; private Object o; public K(Object o, int i) { this.o = o; this.i = i; } public boolean equals(K k) {

问题 I am using LINQ to SQL (SQL Server) with C#. I have a table called "Cars" which automatically becomes the LINQ class/object called "Car". All well and good. Each car has a number of fields, say CarID(primary key int), EngineID, ColourID. I have 10 existing rows in the Cars table. Using all the cool LINQ stuff, I create a new "Car" object in C# with an overloaded constructor that I've created in my "Car" partial class. So for example: Car MyCar = new Car(17, 5); Now this nicely gives me a

问题 I know that equals() will compare the value of objects, the '==' operator will check if the variable point to the same memory. I do not understand how equals() compare the value of objects, for example: class Test { public Test(int x, float y) { this.x = x; this.y = y; } int x, float y; } Test test1 = new Test(1,2.0); Test test2 = new Test(1,2.0); So if I use equals() , will it compare each properties in each object? And what about if we are talking about String? using equals() and operator “

问题 I am trying accomplish the LINQ query below but I need a "not equal" instead of equal, so that filteredEmployees has all employees from groupA minus groupB. List<Employee> groupA = getEmployeeA(); List<Employee> groupB = getEmployeeB(); var filteredEmployees = from a in groupA join b in groupB on a.Name equals b.Name select a; 回答1: You don't need a join for that: var filteredEmployees = groupA.Except(groupB); Note that this will be a sequence of unique employees - so if there are any

问题 This question already has answers here : How to determine equality for two JavaScript objects? (60 answers) Closed 5 years ago . I run the following in console why is the output false. Not asking how to compare two objects but why these two objects are not same. > a = {same:'same'} Object {same: "same"} > b = {same:'same'} Object {same: "same"} > a === b false > a == b false 回答1: Two objects are never the same even if they have the same content, as two different instances of Object is never

问题 This question already has answers here : How to determine equality for two JavaScript objects? (60 answers) Closed 5 years ago . I run the following in console why is the output false. Not asking how to compare two objects but why these two objects are not same. > a = {same:'same'} Object {same: "same"} > b = {same:'same'} Object {same: "same"} > a === b false > a == b false 回答1: Two objects are never the same even if they have the same content, as two different instances of Object is never

问题 I'm having trouble with an equals(Object other) method within a class I'm building called LString . The class contains an object called LString that builds strings out of linked lists, and a few other methods. I'm working on two methods, compareTo() and equals() . The class is tested by running another file, called LStringTest , which outputs this error message: Running compareTo and equals tests (18 tests) Starting tests: .E.........E...E.E Time: 0.426 There were 4 failures: 1)

问题 I have two objects, o1 and o2 from the same class. If o1.hashcode() == o2.hashcode() , can I tell they are the same object? Beside o1==o2 , is there any other way to tell the singleton. 回答1: If you have a single instance of the class, the == and the equals comparison will always return true . However, the hashcode can be equal for different objects, so an equality is not guaranteed just by having equal hashcodes. Here is a nice explanation of the hashcode and equals contracts. Checking the