compareto

问题 beginner Java programmer here. I am trying to compare three strings to each other, and have the system spit out the second/middle word in lexicographic order. import java.util.*; public class Ordered2 { public static void main(String[] args) { String firstString, secondString, thirdString; Scanner keyboard = new Scanner(System.in); System.out.println("Enter three different strings."); System.out.println("The string in the middle order lexicographically will be displayed."); firstString =

问题 The line return array[index1].compareTo(array[index2]); provides an error "Cannot invoke compareTo(double) on the primitive type double" . How to solve this issue? /*:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::*/ /*:: This function implements a comparator of double values :*/ /*:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::*/ private class ArrayIndexComparator implements Comparator<Integer> { private final double[] array; public ArrayIndexComparator

问题 I'm here to ask a specific topic - I really found few info about this on the web. I'm implementing a F# version of Minimax algorithm. The problem I'm having now is that I want to compare Leaf of my tree (data structure below). Searching the erros the VS gave to me I arrived to something like this: The tree type I used to have: type TreeOfPosition = | LeafP of Position | BranchP of Position * TreeOfPosition list and the temptative for implementing the IComparable type staticValue = int [

问题 I am trying to find duplicate words in a string array. Here is my code for the comparison: for ( int j = 0 ; j < wordCount ; j++) { for (int i = wordCount-1 ; i > j ; i--) { if (stringArray[i].compareTo(stringArray[j]) == 0 && i!=j) { //duplicate duplicates++; } } } wordCount -= duplicates; System.out.print("\nNumber of words, not including duplicates: " + wordCount); in the if statement, it says NullPointerException . What does this mean? Is there a better way to do this? I tried simply

问题 So I'm playing around with Compare-Object, and it works fine for comparing files. But what about just strings? Is there a way to find the difference between strings? CompareTo() is good about reporting that there is a difference, but not what the difference is. For example: PS:> $a = "PowerShell rocks" PS:> $b = "Powershell rocks" PS:> $a.CompareTo($b) 1 PS:> Compare-Object -ReferenceObject $a -DifferenceObject $b PS:> Nothing returned. Any way to let me know about the actual difference

问题 I am beginner in java, I am trying to compare two strings in java char by char and find how many different chars they have by the following code but it doesn't work, min is the min between the 2 strings for(int i=0; i<min-1; i++){ s1 = w1.substring(j,j++); s2 = w2.substring(j,j++); if (! s1.equalsIgnoreCase(s2) ){ counter++; } }` Any tips? 回答1: Use this: char[] first = w1.toLowerCase().toCharArray(); char[] second = w2.toLowerCase().toCharArray(); int minLength = Math.min(first.length, second

问题 I'm well aware of the contractual needs to make sure that hashCode is consistent with equals and that equals is consistent with compareTo . However, this is often violated in practice. Are there any tools, techniques, or libraries that can test for this consistency automatically? I suspect unfortunately that the answer is "no," but it would be useful to be able to have a unit test for this sort of thing that could make use of a library call or framework rather than needing to write a custom

问题 An enum in Java implements the Comparable interface. It would have been nice to override Comparable 's compareTo method, but here it's marked as final. The default natural order on Enum 's compareTo is the listed order. Does anyone know why a Java enums have this restriction? 回答1: For consistency I guess... when you see an enum type, you know for a fact that its natural ordering is the order in which the constants are declared. To workaround this, you can easily create your own Comparator

问题 When testing for equality of String 's in Java I have always used equals() because to me this seems to be the most natural method for it. After all, its name already says what it is intended to do. However, a colleague of mine recently told me had been taught to use compareTo() == 0 instead of equals() . This feels unnatural (as compareTo() is meant to provide an ordering and not compare for equality) and even somewhat dangerous (because compareTo() == 0 does not necessarily imply equality in

问题 When testing for equality of String 's in Java I have always used equals() because to me this seems to be the most natural method for it. After all, its name already says what it is intended to do. However, a colleague of mine recently told me had been taught to use compareTo() == 0 instead of equals() . This feels unnatural (as compareTo() is meant to provide an ordering and not compare for equality) and even somewhat dangerous (because compareTo() == 0 does not necessarily imply equality in