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Sort String "13,5,8,4,2,1,9" in ascending order 1,2,4,5,8,9,13 in Java

How can I sort a string "13,5,8,4,2,1,9" in ascendin开发者_Python百科g order, to get 1,2,4,5,8,9,13?


  • Split the string by commas
  • Parse each substring into an integer
  • Sort the resulting collection
  • If you need the result to be a string (it's not clear), convert each integer back into a string and join them together with commas.

If any of those steps causes you difficulties, please be more specific.


  1. Split it into an array of items with String.split().
  2. Convert to an array of numbers with Integer.valueOf().
  3. Sort the array.
  4. Concatenate it all back into a StringBuilder.


As one liner, using Google Collections (updated with Kevin's suggestion)

Joiner.on(",").join(Ordering.natural().onResultOf(new Function<String, Integer>() {
    @Override
    public Integer apply(String from) {
        return Integer.valueOf(from);
    }
}).sortedCopy(Arrays.asList("4,2,7,9,1".split(","))));
  • Split using String.split()
  • Transform to Integer using a Function (anyone know if there's a constant for this one somewhere?)
  • Sort using a TreeSet and natural ordering
  • Join the parts and transform back to a String using Joiner

(old version)

Joiner.on(',').join(
    Sets.newTreeSet(
        Iterables.transform(
            Arrays.asList("13,5,8,4,2,1,9".split(",")),
            new Function<String, Integer>() {
                @Override
                public Integer apply(String from) {
                    return Integer.parseInt(from);
                }}))));


String s = "13,5,8,4,2,1,9";
String[] arr = s.split(",");
Arrays.sort(arr, new Comparator<String>() {
   @Override public int compare(String s1, String s2) {
      return Integer.parseInt(s1) - Integer.parseInt(s2);
   }
});
s = Arrays.toString(arr).replaceAll("[\\[ \\]]", "");

This solution uses:

  • java.util.Comparator
  • java.util.Arrays sort and toString
  • String split and replaceAll
  • regular expression


I would tokenize the string using StringTokenizer,
parse the values (using Integer.parseInt),
then sort the results using Arrays.sort.
Lastly, re-create the string.


String str = "13,5,8,4,2,1,9";
StringTokenizer tokens = new StringTokenizer(", ");
ArrayList<Integer> ints = new ArrayList<Integer>();
for(String token: tokens)
   ints.add(Integer.parseInt(token));

Collection.sort(ints);
String sortedStr = "";
for(int i = 0; i + 1 < ints.size(); ++i)
   sortedStr += ints.get(i) + ", ";
if (ints.size() > 0)
   sortedStr += ints.lastElement();

Might have some misspellings, but I think not. Also, add the appropriate imports yourself =)


So you have a string containing a comma-delimited set of integers that you need to sort and then output to a string? Try split-ting the string, parse-ing the integers, sort-ing the resulting array, and then join-ing the results together


Java 8+

If you are using Java 8 you can use streams to sort like so :

String str = "13,5,8,4,2,1,9";
String sortedString =
        Arrays.stream(str.split(","))             //split with ','
                .map(Integer::valueOf)            //convert your strings to ints
                .sorted()                         //sort 
                .map(String::valueOf)             //convert them back to string
                .collect(Collectors.joining(","));//1,2,4,5,8,9,13

If you want an sorted array you can also use :

Integer[] sortedInts =
        Arrays.stream(str.split(","))    //split with ','
                .map(Integer::valueOf)   //convert your strings to ints
                .sorted()                //sort
                .toArray(Integer[]::new);//[1, 2, 4, 5, 8, 9, 13]

The idea is the same as Jon Skeet explanation.


An alternative using java.util.Scanner

public class SortString {
    public static void main( String [] args ) {
        // Read integers using Scanner...
        Scanner scanner = new Scanner( "13,5,8,4,2,1,9" ).useDelimiter(",");

        // Put them in a Integer list
        List<Integer> list = new ArrayList<Integer>();
        while( scanner.hasNextInt() ){
            list.add( scanner.nextInt() );
        }
        // And sort it
        Collections.sort( list );
        System.out.println( list );
    }
}


ok you can try this one it work in all case.

package com.java;


import java.util.*;

public class cd
{      
  public static void main(String s[])
  {  
        Collections col;
        List l = sort(s);

        System.out.println("\nStrings sorted List ...");
        for(int i = 0; i < s.length; i++)
        {
              System.out.println((String)l.get(i));
        }

        int ints[] = {
                                719, 2, -22, 401, 6
                                };

        Integer in[] = new Integer[ints.length];            
        for(int i = 0; i < in.length; i++)
        {
              in[i] = new Integer(ints[i]);
        }

        l = sort(in);
        System.out.println("\nIntegers sorted List ...");

        for(int i = 0; i < in.length; i++)
        {
              System.out.println((Integer)l.get(i));
        }
}

public static List sort(Object o[])
{
        ArrayList al = new ArrayList();
        for(int i = 0; i < o.length; i++)
        al.add(i, o[i]);
        List list = Collections.synchronizedList(al);
        Collections.sort(list);
        return list;
}

}


This is one way to sorting.

package com.java;


import java.util.ArrayList;

import java.util.Collections;


public class b{

public static void main(String[] args) {
//create an ArrayList object

ArrayList arrayList = new ArrayList();


//Add elements to Arraylist

arrayList.add("9");
arrayList.add("3");
arrayList.add("5");
arrayList.add("2");
arrayList.add("4");

Collections.sort(arrayList);


//display elements of ArrayList

System.out.println("ArrayList elements after sorting in ascending order : ");

for(int i=0; i<arrayList.size(); i++)

System.out.println(arrayList.get(i));



}

}


class SplitStr
{
  public static void main(String args[])
  {
    try
    {
      String str=args[0]+","+args[1];    //marge two string in one
      String sArr[]=str.split(",");
      int slen=sArr.length;
      int iArr[]=new int[slen];
      int temp;
      for(int i=0;i<slen;i++)
      {
       iArr[i]=Integer.parseInt(sArr[i]);   //convert String into integer array

      }
      for(int i=0;i<slen;i++)
      {
        for(int j=i+1;j<slen;j++)
        {
          if(iArr[i]>=iArr[j])
          {
            temp=iArr[i];
            iArr[i]=iArr[j];
            iArr[j]=temp;
          }
        }
      }
      for(int i=0;i<slen;i++)
      {
        System.out.println(" "+iArr[i]);
      }
    }
    catch(Exception e)
    {
      System.out.println("input error "+e);
    }
  }
}


Bash is SO powerful :-)

numbers="1, 2, 9, 4, 7, 5" ; for number in $(echo "$numbers") ; do echo "$number" | tr -d ", "; done | sort | tr "\n" "," ; echo ""
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