How to sort rows so that values ​​with additional information are displayed first?

Question

I am trying to sort the following lines

1.0.0.0-00000000-00000 2.1.0.0 2.2.0.0 2.3.0.0-00000000-00000 

These values ​​are currently stored in an array of strings.

  String[] arrays = {"1.0.0.0-00000000-00000", "2.1.0.0", "2.2.0.0", "2.3.0.0-00000000-00000"}; 

I am trying to get the output where, if there is no "-", then these values ​​go to the end of my array in sorted order. I am trying to get the output as follows:

 1.0.0.0-00000000-00000 2.3.0.0-00000000-00000 2.1.0.0 2.2.0.0 

I tried Arrays.sort(arrays) but I'm not sure how to do this?

 import java.util.Arrays; import java.util.Comparator; import java.util.Collections; public class HelloWorld{ public static void main(String []args){ String[] arrays = {"1.0.0.0-00000000-00000", "2.1.0.0", "2.2.0.0", "2.3.0.0-00000000-00000"}; String[] newArray = new String[arrays.length]; class CustomComparator implements Comparator<String> { @Override public int compare(String a, String b) { if(a.contains("-") && !b.contains("-")) return 1; else if(!a.contains("-") && b.contains("-")) return -1; return a.compareTo(b); } } Arrays.sort(arrays, new CustomComparator()); for(String array : arrays) { System.out.println(array); } } } Error: $javac HelloWorld.java 2>&1 HelloWorld.java:25: error: no suitable method found for sort(String[],CustomComparator) Collections.sort(arrays, new CustomComparator()); ^ method Collections.<T#1>sort(List<T#1>,Comparator<? super T#1>) is not applicable (no instance(s) of type variable(s) T#1 exist so that argument type String[] conforms to formal parameter type List<T#1>) method Collections.<T#2>sort(List<T#2>) is not applicable (cannot instantiate from arguments because actual and formal argument lists differ in length) where T#1,T#2 are type-variables: T#1 extends Object declared in method <T#1>sort(List<T#1>,Comparator<? super T#1>) T#2 extends Comparable<? super T#2> declared in method <T#2>sort(List<T#2>) 1 error The method gave me an output of 2.1.0.0 2.2.0.0 1.0.0.0-00000000-00000 2.3.0.0-00000000-00000 as opposed to 1.0.0.0-00000000-00000 2.3.0.0-00000000-00000 2.1.0.0 2.2.0.0 

Answer 1

Use comparator

  import java.util.Comparator; class CustomComparator implements Comparator<String> { @Override public int compare(String a, String b) { if(a.contains("-") && !b.contains("-")) return 1; else if(!a.contains("-") && b.contains("-")) return -1; return a.compareTo(b); } } Collections.sort(arrays, new CustomComparator()); 

return a negative value means b comes before a, and a positive value means a comes before b

Answer 2

Smaller values ​​start earlier than others. Change Comparator below

 class CustomComparator implements Comparator<String> { @Override public int compare(String a, String b) { if(a.contains("-") && !b.contains("-")) return -1; else if(!a.contains("-") && b.contains("-")) return 1; return a.compareTo(b); } } 

Answer 3

  int dashed = 0; //How many strings with a "-" are there? for (String s : arrays) if ( s.contains("-") ) ++dashed; int undashed = arrays.length - dashed; dashed = 0; Arrays.sort(arrays); for (String s : arrays) if ( s.contains("-") ) newArray[dashed++] = s; else newArray[undashed++] = s; 

It is simple and will work regardless of the size of the array, strings or additional information. Just import java.util.Arrays for Arrays.sort. There is no reason to do unnecessary things when simplicity is possible.