Sorting the characters in a utf-16 string in java





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tl;dr



Java uses 2 chars to represent UTF-16. Using Arrays.sort (unstable sort), messes with char sequencing. Should I convert char to int or is there a better way?



Details



Java represents Character as UTF-16. But Character class itself wraps char(16 bit). For UTF-16, it will be array of 2 char(32 bit).



Sorting String of UTF-16 chars using inbuilt sort messes with data.
(Arrays.sort uses Dual Pivot Quick sort and Collections.sort uses Arrays.sort to do heavy lifting.)



To be specific, do you convert char to int or is there a better way to sort?



import java.util.Arrays;

public class Main {
public static void main(String args) {
int utfCodes = {128513, 128531, 128557};
String emojis = new String(utfCodes, 0, 3);
System.out.println("Initial String: " + emojis);

char chars = emojis.toCharArray();
Arrays.sort(chars);
System.out.println("Sorted String: " + new String(chars));
}
}


Output:



Initial String: 😁😓😭
Sorted String: ??😁??









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  • This is what we call a "Collation". You should use a library for this because there are many collations to choose from.

    – Guillaume F.
    1 hour ago


















8















tl;dr



Java uses 2 chars to represent UTF-16. Using Arrays.sort (unstable sort), messes with char sequencing. Should I convert char to int or is there a better way?



Details



Java represents Character as UTF-16. But Character class itself wraps char(16 bit). For UTF-16, it will be array of 2 char(32 bit).



Sorting String of UTF-16 chars using inbuilt sort messes with data.
(Arrays.sort uses Dual Pivot Quick sort and Collections.sort uses Arrays.sort to do heavy lifting.)



To be specific, do you convert char to int or is there a better way to sort?



import java.util.Arrays;

public class Main {
public static void main(String args) {
int utfCodes = {128513, 128531, 128557};
String emojis = new String(utfCodes, 0, 3);
System.out.println("Initial String: " + emojis);

char chars = emojis.toCharArray();
Arrays.sort(chars);
System.out.println("Sorted String: " + new String(chars));
}
}


Output:



Initial String: 😁😓😭
Sorted String: ??😁??









share|improve this question









New contributor




dingy is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.





















  • This is what we call a "Collation". You should use a library for this because there are many collations to choose from.

    – Guillaume F.
    1 hour ago














8












8








8








tl;dr



Java uses 2 chars to represent UTF-16. Using Arrays.sort (unstable sort), messes with char sequencing. Should I convert char to int or is there a better way?



Details



Java represents Character as UTF-16. But Character class itself wraps char(16 bit). For UTF-16, it will be array of 2 char(32 bit).



Sorting String of UTF-16 chars using inbuilt sort messes with data.
(Arrays.sort uses Dual Pivot Quick sort and Collections.sort uses Arrays.sort to do heavy lifting.)



To be specific, do you convert char to int or is there a better way to sort?



import java.util.Arrays;

public class Main {
public static void main(String args) {
int utfCodes = {128513, 128531, 128557};
String emojis = new String(utfCodes, 0, 3);
System.out.println("Initial String: " + emojis);

char chars = emojis.toCharArray();
Arrays.sort(chars);
System.out.println("Sorted String: " + new String(chars));
}
}


Output:



Initial String: 😁😓😭
Sorted String: ??😁??









share|improve this question









New contributor




dingy is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.












tl;dr



Java uses 2 chars to represent UTF-16. Using Arrays.sort (unstable sort), messes with char sequencing. Should I convert char to int or is there a better way?



Details



Java represents Character as UTF-16. But Character class itself wraps char(16 bit). For UTF-16, it will be array of 2 char(32 bit).



Sorting String of UTF-16 chars using inbuilt sort messes with data.
(Arrays.sort uses Dual Pivot Quick sort and Collections.sort uses Arrays.sort to do heavy lifting.)



To be specific, do you convert char to int or is there a better way to sort?



import java.util.Arrays;

public class Main {
public static void main(String args) {
int utfCodes = {128513, 128531, 128557};
String emojis = new String(utfCodes, 0, 3);
System.out.println("Initial String: " + emojis);

char chars = emojis.toCharArray();
Arrays.sort(chars);
System.out.println("Sorted String: " + new String(chars));
}
}


Output:



Initial String: 😁😓😭
Sorted String: ??😁??






java string sorting utf-16






share|improve this question









New contributor




dingy is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











share|improve this question









New contributor




dingy is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









share|improve this question




share|improve this question








edited 2 hours ago









jtahlborn

47.6k56198




47.6k56198






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asked 2 hours ago









dingydingy

413




413




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New contributor





dingy is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






dingy is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.













  • This is what we call a "Collation". You should use a library for this because there are many collations to choose from.

    – Guillaume F.
    1 hour ago



















  • This is what we call a "Collation". You should use a library for this because there are many collations to choose from.

    – Guillaume F.
    1 hour ago

















This is what we call a "Collation". You should use a library for this because there are many collations to choose from.

– Guillaume F.
1 hour ago





This is what we call a "Collation". You should use a library for this because there are many collations to choose from.

– Guillaume F.
1 hour ago












3 Answers
3






active

oldest

votes


















1














I looked around for a bit and couldn't find any clean ways to sort an array by groupings of two elements without the use of a library.



Luckily, the codePoints of the String are what you used to create the String itself in this example, so you can simply sort those and create a new String with the result.



public static void main(String args) {
int utfCodes = {128531, 128557, 128513};
String emojis = new String(utfCodes, 0, 3);
System.out.println("Initial String: " + emojis);

int codePoints = emojis.codePoints().sorted().toArray();
System.out.println("Sorted String: " + new String(codePoints, 0, 3));
}



Initial String: 😓😭😁



Sorted String: 😁😓😭




I switched the order of the characters in your example because they were already sorted.






share|improve this answer

































    1














    We can't use char for Unicode, because Java's Unicode char handling is broken.



    In the early days of Java, Unicode code points were always 16-bits (fixed size at exactly one char). However, the Unicode specification changed to allow supplemental characters. That meant Unicode characters are now variable widths, and can be longer than one char. Unfortunately, it was too late to change Java's char implementation without breaking a ton of production code.



    So the best way to manipulate Unicode characters is by using code points directly, e.g., using String.codePointAt(index) or the String.codePoints() stream on JDK 1.8 and above.






    share|improve this answer








    New contributor




    peekay is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
    Check out our Code of Conduct.




























      1














      If you are using Java 8 or later, then this is a simple way to sort the characters in a string while respecting (not breaking) multi-char codepoints:



      int codepoints = someString.codePoints().sort().toArray();
      String sorted = new String(codepoints, 0, codepoints.length);


      Prior to Java 8, I think you either need to use a loop to iterate the code points in the original string, or use a 3rd-party library method.





      Fortunately, sorting the codepoints in a String is uncommon enough that the clunkyness and inefficiency of the solutions above are rarely a concern.



      (When was the last time you tested for anagrams of emojis?)






      share|improve this answer


























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        3 Answers
        3






        active

        oldest

        votes








        3 Answers
        3






        active

        oldest

        votes









        active

        oldest

        votes






        active

        oldest

        votes









        1














        I looked around for a bit and couldn't find any clean ways to sort an array by groupings of two elements without the use of a library.



        Luckily, the codePoints of the String are what you used to create the String itself in this example, so you can simply sort those and create a new String with the result.



        public static void main(String args) {
        int utfCodes = {128531, 128557, 128513};
        String emojis = new String(utfCodes, 0, 3);
        System.out.println("Initial String: " + emojis);

        int codePoints = emojis.codePoints().sorted().toArray();
        System.out.println("Sorted String: " + new String(codePoints, 0, 3));
        }



        Initial String: 😓😭😁



        Sorted String: 😁😓😭




        I switched the order of the characters in your example because they were already sorted.






        share|improve this answer






























          1














          I looked around for a bit and couldn't find any clean ways to sort an array by groupings of two elements without the use of a library.



          Luckily, the codePoints of the String are what you used to create the String itself in this example, so you can simply sort those and create a new String with the result.



          public static void main(String args) {
          int utfCodes = {128531, 128557, 128513};
          String emojis = new String(utfCodes, 0, 3);
          System.out.println("Initial String: " + emojis);

          int codePoints = emojis.codePoints().sorted().toArray();
          System.out.println("Sorted String: " + new String(codePoints, 0, 3));
          }



          Initial String: 😓😭😁



          Sorted String: 😁😓😭




          I switched the order of the characters in your example because they were already sorted.






          share|improve this answer




























            1












            1








            1







            I looked around for a bit and couldn't find any clean ways to sort an array by groupings of two elements without the use of a library.



            Luckily, the codePoints of the String are what you used to create the String itself in this example, so you can simply sort those and create a new String with the result.



            public static void main(String args) {
            int utfCodes = {128531, 128557, 128513};
            String emojis = new String(utfCodes, 0, 3);
            System.out.println("Initial String: " + emojis);

            int codePoints = emojis.codePoints().sorted().toArray();
            System.out.println("Sorted String: " + new String(codePoints, 0, 3));
            }



            Initial String: 😓😭😁



            Sorted String: 😁😓😭




            I switched the order of the characters in your example because they were already sorted.






            share|improve this answer















            I looked around for a bit and couldn't find any clean ways to sort an array by groupings of two elements without the use of a library.



            Luckily, the codePoints of the String are what you used to create the String itself in this example, so you can simply sort those and create a new String with the result.



            public static void main(String args) {
            int utfCodes = {128531, 128557, 128513};
            String emojis = new String(utfCodes, 0, 3);
            System.out.println("Initial String: " + emojis);

            int codePoints = emojis.codePoints().sorted().toArray();
            System.out.println("Sorted String: " + new String(codePoints, 0, 3));
            }



            Initial String: 😓😭😁



            Sorted String: 😁😓😭




            I switched the order of the characters in your example because they were already sorted.







            share|improve this answer














            share|improve this answer



            share|improve this answer








            edited 1 hour ago

























            answered 1 hour ago









            Jacob G.Jacob G.

            16.9k52466




            16.9k52466

























                1














                We can't use char for Unicode, because Java's Unicode char handling is broken.



                In the early days of Java, Unicode code points were always 16-bits (fixed size at exactly one char). However, the Unicode specification changed to allow supplemental characters. That meant Unicode characters are now variable widths, and can be longer than one char. Unfortunately, it was too late to change Java's char implementation without breaking a ton of production code.



                So the best way to manipulate Unicode characters is by using code points directly, e.g., using String.codePointAt(index) or the String.codePoints() stream on JDK 1.8 and above.






                share|improve this answer








                New contributor




                peekay is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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                  1














                  We can't use char for Unicode, because Java's Unicode char handling is broken.



                  In the early days of Java, Unicode code points were always 16-bits (fixed size at exactly one char). However, the Unicode specification changed to allow supplemental characters. That meant Unicode characters are now variable widths, and can be longer than one char. Unfortunately, it was too late to change Java's char implementation without breaking a ton of production code.



                  So the best way to manipulate Unicode characters is by using code points directly, e.g., using String.codePointAt(index) or the String.codePoints() stream on JDK 1.8 and above.






                  share|improve this answer








                  New contributor




                  peekay is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                  Check out our Code of Conduct.























                    1












                    1








                    1







                    We can't use char for Unicode, because Java's Unicode char handling is broken.



                    In the early days of Java, Unicode code points were always 16-bits (fixed size at exactly one char). However, the Unicode specification changed to allow supplemental characters. That meant Unicode characters are now variable widths, and can be longer than one char. Unfortunately, it was too late to change Java's char implementation without breaking a ton of production code.



                    So the best way to manipulate Unicode characters is by using code points directly, e.g., using String.codePointAt(index) or the String.codePoints() stream on JDK 1.8 and above.






                    share|improve this answer








                    New contributor




                    peekay is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                    Check out our Code of Conduct.










                    We can't use char for Unicode, because Java's Unicode char handling is broken.



                    In the early days of Java, Unicode code points were always 16-bits (fixed size at exactly one char). However, the Unicode specification changed to allow supplemental characters. That meant Unicode characters are now variable widths, and can be longer than one char. Unfortunately, it was too late to change Java's char implementation without breaking a ton of production code.



                    So the best way to manipulate Unicode characters is by using code points directly, e.g., using String.codePointAt(index) or the String.codePoints() stream on JDK 1.8 and above.







                    share|improve this answer








                    New contributor




                    peekay is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                    Check out our Code of Conduct.









                    share|improve this answer



                    share|improve this answer






                    New contributor




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                    answered 1 hour ago









                    peekaypeekay

                    1963




                    1963




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                    New contributor





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                        1














                        If you are using Java 8 or later, then this is a simple way to sort the characters in a string while respecting (not breaking) multi-char codepoints:



                        int codepoints = someString.codePoints().sort().toArray();
                        String sorted = new String(codepoints, 0, codepoints.length);


                        Prior to Java 8, I think you either need to use a loop to iterate the code points in the original string, or use a 3rd-party library method.





                        Fortunately, sorting the codepoints in a String is uncommon enough that the clunkyness and inefficiency of the solutions above are rarely a concern.



                        (When was the last time you tested for anagrams of emojis?)






                        share|improve this answer






























                          1














                          If you are using Java 8 or later, then this is a simple way to sort the characters in a string while respecting (not breaking) multi-char codepoints:



                          int codepoints = someString.codePoints().sort().toArray();
                          String sorted = new String(codepoints, 0, codepoints.length);


                          Prior to Java 8, I think you either need to use a loop to iterate the code points in the original string, or use a 3rd-party library method.





                          Fortunately, sorting the codepoints in a String is uncommon enough that the clunkyness and inefficiency of the solutions above are rarely a concern.



                          (When was the last time you tested for anagrams of emojis?)






                          share|improve this answer




























                            1












                            1








                            1







                            If you are using Java 8 or later, then this is a simple way to sort the characters in a string while respecting (not breaking) multi-char codepoints:



                            int codepoints = someString.codePoints().sort().toArray();
                            String sorted = new String(codepoints, 0, codepoints.length);


                            Prior to Java 8, I think you either need to use a loop to iterate the code points in the original string, or use a 3rd-party library method.





                            Fortunately, sorting the codepoints in a String is uncommon enough that the clunkyness and inefficiency of the solutions above are rarely a concern.



                            (When was the last time you tested for anagrams of emojis?)






                            share|improve this answer















                            If you are using Java 8 or later, then this is a simple way to sort the characters in a string while respecting (not breaking) multi-char codepoints:



                            int codepoints = someString.codePoints().sort().toArray();
                            String sorted = new String(codepoints, 0, codepoints.length);


                            Prior to Java 8, I think you either need to use a loop to iterate the code points in the original string, or use a 3rd-party library method.





                            Fortunately, sorting the codepoints in a String is uncommon enough that the clunkyness and inefficiency of the solutions above are rarely a concern.



                            (When was the last time you tested for anagrams of emojis?)







                            share|improve this answer














                            share|improve this answer



                            share|improve this answer








                            edited 1 min ago

























                            answered 1 hour ago









                            Stephen CStephen C

                            528k72590946




                            528k72590946






















                                dingy is a new contributor. Be nice, and check out our Code of Conduct.










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