comparable

Help comparing float member variables using Comparators

由 a 夏天 提交于 2019-12-08 16:39:07
问题 I am able to compare Strings fine, but would like to know how I can rank floating point numbers? getChange() returns a String. I want to be able to sort descending. How can I do this? UPDATE: package org.stocktwits.helper; import java.util.Comparator; import org.stocktwits.model.Quote; public class ChangeComparator implements Comparator<Quote> { public int compare(Quote o1, Quote o2) { float change1 = Float.valueOf(o1.getChange()); float change2 = Float.valueOf(o2.getChange()); if (change1 <

C++ determine if class is comparable

由 人走茶凉 提交于 2019-12-08 15:24:17
问题 I'm more or less Java programmer, so this might be a stupid question, but I didn't manage to find any simple solution. I have a class like this in C++: template<class T> class Node {...} And I need T to be comparable - to have at least == < > operators defined. Is there any simple way to do this - or what is the best practice for this? In Java, it would be something like this: public class Node<T extends Comparable> { ... } Thanks for your help! 回答1: C++ templates are duck-typed, so no

How to write a method signature “T that implements Comparable<T>” in Java?

由 前提是你 提交于 2019-12-08 07:00:43
问题 What signature should I have on my insert -method? I'm struggling with the generics. In a way, I want both Comparable<T> and T and I have tried with <Comparable<T> extends T> . public class Node<T> { private Comparable<T> value; public Node(Comparable<T> val) { this.value = val; } // WRONG signature - compareTo need an argument of type T public void insert(Comparable<T> val) { if(value.compareTo(val) > 0) { new Node<T>(val); } } public static void main(String[] args) { Integer i4 = new

Kotlin sort array by value in range

由 别来无恙 提交于 2019-12-08 01:22:48
问题 Let's have a class Player(val position: Int, val time: Float) and we want to sort an array or list of players by position . If some of these players have the same position after first sorting, we want to sort them by time in groups. By group I mean set of players with the same position. I know about list.sortedWith(compareBy<Foo> { it.a }.thenByDescending { it.b }.thenBy { it.c }) But of course it does not solve this case. Is there any smart way in Kotlin to achieve this simple task? We can

understanding comparable mixin and enumerable mixin

由 旧城冷巷雨未停 提交于 2019-12-07 04:01:28
问题 I am a newbie and learning ruby. Would like to have a better understanding of the question asked. I don't understand the use of comparable mixin and enumerable mixin. I mean we don't include these in our class when we need to use them, right? if we want to compare two objects we simply write x > y. Then what is the use of explicitly using them? 回答1: Great Question Akash! Sometimes it's not "simple" how two objects can be compared! What if you have a Dog class? How do you compare two Dog

java: sort array1 based on array2

由 北战南征 提交于 2019-12-06 17:09:44
问题 Thanks for the help from Zirak In my previous post i implemented the following in JavaScript: var arr1 =[0,1,2,3]; var arr2 =["ac", "bc", "ad", "e"]; var result = arr1 .sort(function(i, j){return arr2[i].localeCompare(arr2[j])}) document.write(result ); The way to achieve this is quite compact in JavaScript, can a java implementation of this be also achieved by such simplicity? I could only think of implementing the Comparable interface like the following: public class testCompare { public

Kotlin sort array by value in range

由 感情迁移 提交于 2019-12-06 11:19:47
Let's have a class Player(val position: Int, val time: Float) and we want to sort an array or list of players by position . If some of these players have the same position after first sorting, we want to sort them by time in groups. By group I mean set of players with the same position. I know about list.sortedWith(compareBy<Foo> { it.a }.thenByDescending { it.b }.thenBy { it.c }) But of course it does not solve this case. Is there any smart way in Kotlin to achieve this simple task? We can sort it manually by checking positions and swapping items, but I wonder if Kotlin has something to say

LINQ: Use .Except() on collections of different types by making them convertible/comparable?

由 て烟熏妆下的殇ゞ 提交于 2019-12-06 02:09:26
问题 Given two lists of different types, is it possible to make those types convertible between or comparable to each other (eg with a TypeConverter or similar) so that a LINQ query can compare them? I've seen other similar questions on SO but nothing that points to making the types convertible between each other to solve the problem. Collection Types: public class Data { public int ID { get; set; } } public class ViewModel { private Data _data; public ViewModel(Data data) { _data = data; } }

understanding comparable mixin and enumerable mixin

由 依然范特西╮ 提交于 2019-12-05 08:18:43
I am a newbie and learning ruby. Would like to have a better understanding of the question asked. I don't understand the use of comparable mixin and enumerable mixin. I mean we don't include these in our class when we need to use them, right? if we want to compare two objects we simply write x > y. Then what is the use of explicitly using them? Great Question Akash! Sometimes it's not "simple" how two objects can be compared! What if you have a Dog class? How do you compare two Dog instances? What should be the comparison based on? Is it enough to compare their name? their breed? their DNA? It

Java Syntax for a list of comparable objects

由 孤人 提交于 2019-12-05 08:06:00
I'm writing a method that takes as its only parameter a list of comparable objects and doesn't return anything. I am uncertain as to the syntax that it should have: public static void methodName(List<Comparable<Object>> list) { // Do some stuff } I think this is wrong because of the <Object> as a type for Comparable, which would mean the list can take an Integer and a Boolean as objects, but I don't want that. I want the list to take only one type, but that type has to implement the Comparable interface. How do I achieve that? Maybe make it generic? public static <E extends Comparable<E>> void
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