Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.java.programmer > #36684

Re: How to parse an array?

Show all headers | View raw

On 6/20/2017 14:18, Eric Douglas wrote:
> I'm writing a method to take 2 arrays and return the subset of the first array.  Is there a more efficient way than creating a new array and iterating?
> 
> ArrayList<String> list1 = new ArrayList();
> list1.add("AA");
> list1.add("CC");
> list1.add("DD");
> list1.add("BB");
> list1.add("EE");
> ArrayList<Integer> list2 = new ArrayList();
> list2.add(1);
> list2.add(3);
> ArrayList<String> retval = new ArrayList();
> for (int i : list2) {
>       retval.add(list1.get(i));
> }
> Collections.sort(retval);
> System.out.println(retval);
> 

I have no idea if it is efficient or not:

import java.util.*;
import java.util.stream.*;
import static java.util.stream.Collectors.*;

public class test4 {
     public static void main(String... args) {
         List<String> list1 = Arrays.asList("AA","CC","DD","BB","EE");
         List<Integer> list2 = Arrays.asList(1,3);

         List<String> list = list2.stream().
          map(i -> list1.get(i)).sorted().
          collect(toList());
         System.out.println(list);
     }
}



-- 

Knute Johnson

Back to comp.lang.java.programmer | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

How to parse an array? Eric Douglas <e.d.programmer@gmail.com> - 2017-06-20 12:18 -0700
  Re: How to parse an array? Knute Johnson <nospam@rabbitbrush.frazmtn.com> - 2017-06-20 14:49 -0500
  Re: How to parse an array? Arne Vajhøj <arne@vajhoej.dk> - 2017-06-20 16:15 -0400
  Re: How to parse an array? Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-06-20 16:23 -0400
  Re: How to parse an array? Robert Klemme <shortcutter@googlemail.com> - 2017-06-24 12:02 +0200
    Re: How to parse an array? Eric Douglas <e.d.programmer@gmail.com> - 2017-06-26 05:10 -0700
      Re: How to parse an array? Eric Sosman <esosman@comcast-dot-net.invalid> - 2017-06-26 09:36 -0400
        Re: How to parse an array? Eric Douglas <e.d.programmer@gmail.com> - 2017-06-26 07:47 -0700
          Re: How to parse an array? Martin Gregorie <martin@address-in-sig.invalid> - 2017-06-26 15:47 +0000
        Re: How to parse an array? Arne Vajhøj <arne@vajhoej.dk> - 2017-06-26 20:37 -0400
      Re: How to parse an array? lewbloch@gmail.com - 2017-06-27 12:29 -0700
        Re: How to parse an array? Eric Douglas <e.d.programmer@gmail.com> - 2017-06-27 12:50 -0700
          Re: How to parse an array? Martin Gregorie <martin@address-in-sig.invalid> - 2017-06-27 20:05 +0000
            Re: How to parse an array? Eric Douglas <e.d.programmer@gmail.com> - 2017-06-27 14:01 -0700
              Re: How to parse an array? Martin Gregorie <martin@address-in-sig.invalid> - 2017-06-27 22:34 +0000
                Re: How to parse an array? Eric Douglas <e.d.programmer@gmail.com> - 2017-06-28 05:10 -0700
                Re: How to parse an array? Martin Gregorie <martin@address-in-sig.invalid> - 2017-06-28 19:09 +0000
                Re: How to parse an array? Eric Douglas <e.d.programmer@gmail.com> - 2017-06-28 13:02 -0700
                Re: How to parse an array? Martin Gregorie <martin@address-in-sig.invalid> - 2017-06-28 21:55 +0000
                Re: How to parse an array? Eric Douglas <e.d.programmer@gmail.com> - 2017-06-30 06:10 -0700
                Re: How to parse an array? Martin Gregorie <martin@address-in-sig.invalid> - 2017-06-30 16:52 +0000
  Re: How to parse an array? Jerry Stuckle <jstucklex@attglobal.net> - 2017-06-24 16:34 -0400
    Re: How to parse an array? Martin Gregorie <martin@address-in-sig.invalid> - 2017-06-24 22:42 +0000
      Re: How to parse an array? Jerry Stuckle <jstucklex@attglobal.net> - 2017-06-24 20:05 -0400
      Re: How to parse an array? Robert Klemme <shortcutter@googlemail.com> - 2017-06-25 12:20 +0200

csiph-web