String Array Sorting

Question 1. Anybody know how to easily sort a string array?
Question 2. Is there any good data base management VI's out there anywhere?
Thank you

> Question 1. Anybody know how to easily sort a string array?
>
There is this icon in the Array palette called Sort 1D Array. You might want
to give it a try.
> Question 2. Is there any good data base management VI's out there anywhere?
>
There may be some freebie stuff floating around, but I know that NI has
an SQL add-on for communicating with most standard databases. As mentioned
in a previous posting this morning, you can also use ActiveX if that is
more convenient/easier for you. From my experience, most people find the
SQL approach easier once they get past the three letter acronym.
Greg McKaskle

Similar Messages

Newbie trying to sort 2D string array

Dear all,
After read some book chapters, web sites including this, I still don't get the point.
If I have a file like,
1 aaa 213 0.9
3 cbb 514 0.1
2 abc 219 1.3
9 bbc 417 10.4
8 dee 887 2.1
9 bba 111 7.1
and I load into memory as a String[][]
here comes the problem, I sort by column 1 (aaa,...,bba) using an adaptation of the Quicksort algorithm for 2D arrays
* Sort for a 2D String array
* @param a an String 2D array
* @param column column to be sort
public static void sort(String[][] a, int column) throws Exception {
QuickSort(a, 0, a.length - 1, column);
/** Sort elements using QuickSort algorithm
static void QuickSort(String[][] a, int lo0, int hi0, int column) throws Exception {
int lo = lo0;
int hi = hi0;
int mid;
String mitad;
if ( hi0 > lo0) {
/* Arbitrarily establishing partition element as the midpoint of
* the array.
mid = ( lo0 + hi0 ) / 2 ;
mitad = a[mid][column];
// loop through the array until indices cross
while( lo <= hi ) {
/* find the first element that is greater than or equal to
* the partition element starting from the left Index.
while( ( lo < hi0 ) && ( a[lo][column].compareTo(mitad)<0))
++lo;
/* find an element that is smaller than or equal to
* the partition element starting from the right Index.
while( ( hi > lo0 ) && ( a[hi][column].compareTo(mitad)>0))
--hi;
// if the indexes have not crossed, swap
if( lo <= hi )
swap(a, lo, hi);
++lo;
--hi;
/* If the right index has not reached the left side of array
* must now sort the left partition.
if( lo0 < hi )
QuickSort( a, lo0, hi, column );
/* If the left index has not reached the right side of array
* must now sort the right partition.
if( lo < hi0 )
QuickSort( a, lo, hi0, column );
* swap 2D String column
private static void swap(String[][] array, int k1, int k2){
String[] temp = array[k1];
array[k1] = array[k2];
array[k2] = temp;
----- end of the code --------
if I call this from the main module like this
import MyUtil.*;
public class kaka
public static void main(String[] args) throws Exception
String[][]a = MyUtil.fileToArray("array.txt");
MyMatrix.printf(a);
System.out.println("");
MyMatrix.sort(a,1);
MyMatrix.printf(a);
System.out.println("");
MyMatrix.sort(a,3);
MyMatrix.printf(a);
for the first sorting I get
1 aaa 213 0.9
2 abc 219 1.3
9 bba 111 7.1
9 bbc 417 10.4
3 cbb 514 0.1
8 dee 887 2.1
(lexicographic)
but for the second one (column 3) I get
3 cbb 514 0.1
1 aaa 213 0.9
2 abc 219 1.3
9 bbc 417 10.4
8 dee 887 2.1
9 bba 111 7.1
this is not the order I want to apply to this sorting, I would like to create my own one. but or I can't or I don't know how to use a comparator on this case.
I don't know if I am rediscovering the wheel with my (Sort String[][], but I think that has be an easy way to sort arrays of arrays better than this one.
I've been trying to understand the Question of the week 106 (http://developer.java.sun.com/developer/qow/archive/106/) that sounds similar, and perfect for my case. But I don't know how to pass my arrays values to the class Fred().
Any help will be deeply appreciated
Thanks for your help and your attention
Pedro

public class StringArrayComparator implements Comparator {
int sortColumn = 0;
public int setSortColumn(c) { sortColumn = c; }
public int compareTo(Object o1, Object o2) {
    if (o1 == null && o2 == null)
      return 0;
    if (o1 == null)
      return -1;
    if (o2 == null)
      return 1;
    String[] s1 = (String[])o1;
    String[] s2 = (String[])o2;
    // I assume the elements at position sortColumn is
    // not null nor out of bounds.
    return s1[sortColumn].compareTo(s2[sortColumn]);
// Then you can use this to sort the 2D array:
Comparator comparator = new StringArrayComparator();
comparator.setSortColumn(0); // sort by first column
String[][] array = ...
Arrays.sort(array, comparator);I haven't tested the code, so there might be some compiler errors, or an error in the logic.

Arrays.sort() issue when Numbers are a string!

Hey guys -- here is my problem.
I am working on a TOP TEN SCORES mechanism for a trivia game. I have read in the score and the players name from a file. SO I have 2 different arrays topScores[] and topNames[] ---
Now if someone plays the game and has a higher score than the lowest score, they get to put their score and name in the file and replace the low score.
HOWEVER -- I do not know how to sort topSCORES[] and then make whatever sorted changes apply also to the topNAMES[] array.
SO I thought - HEY I will concatenate the topScores and topNames into a single String array. And then SORT! This sounded like a great idea until I realized that the following will happen:
100 tvance (first one)
1000 dvance (second score)
250 danderson (third score) !!!
See my problem? When I sort this way - it is sorting alphabetically so it will put a 1000 score before a 200-900 score! ---
**I hope I explained this adequately -- can someone help? Is there a way to sort the topScores array and have it also change the order of the topNames array as well?

Create a new class - HighScore, which has a highScore and a name?Yup. This technique even has a name: object-oriented programming!
Demo:
import java.util.*;
public final class HighScore implements Comparable<HighScore> {
    private final int score;
    private final String name;
    public HighScore(int score, String name) {
        if (name == null)
            throw new NullPointerException();
        this.score = score;
        this.name = name;
    public int getScore() {
        return score;
    public String getName() {
        return name;
    public int compareTo(HighScore that) {
        if (this.score < that.score)
            return -1;
        else if (this.score > that.score)
            return +1;
        else
            return this.name.compareTo(that.name);
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        else if (obj instanceof HighScore) {
            HighScore that = (HighScore) obj;
            return this.score == that.score && this.name == that.name;
        } else
            return false;
    public int hashCode() {
        return score ^ name.hashCode();
    public String toString() {
        return score + " " + name;
    //demo
    public static void main(String[] args) {
        HighScore[] top = {
            new HighScore(250, "danderson"),
            new HighScore(1000, "dvance"),
            new HighScore(100, "dvance")
        Arrays.sort(top);
        for(int i=0; i<top.length; ++i) {
            System.out.println(top);
If you are using an older version of Java (1.4 or earlier), the generics won't be
recognized. In that case the class definition would begin:
public final class HighScore implements Comparable {And the compareTo method would begin:
public int compareTo(Object obj) {
    HighScore that = (HighScore) obj;Good luck!

TreeSet vs Collection.Sort / Array.sort for Strings

Gurus
I am pondering weather to use TreeSet vs the Collections.sort / Array.sort for sorting Strings.
Basically I have a list of Strings, i need to perform the following operations on these Strings
1) Able to list Strings starting with a Prefix
2) Able to list Strings Lexically greater than a String
Any help would be greatly appreciated!
Thanks a bunch

SpaceShuttle wrote:
Gurus
I am pondering weather to use TreeSet vs the Collections.sort / Array.sort for sorting Strings.
Basically I have a list of Strings, i need to perform the following operations on these Strings
1) Able to list Strings starting with a Prefix
2) Able to list Strings Lexically greater than a String
Any help would be greatly appreciated!
Thanks a bunchBig-O wise, there's no difference between sorting a list of N elements or inserting them one by one in a tree-set. Both take O(n*log(n)). But both collections are not well suited for looking up string that start with a certain substring. In that case you had better use a Patricia tree (or Radix tree).
Good luck.

Sorting 2D string array

Hi I am new to labview. I want to sort my 2D string array by col 1. But I dont know how to sort it perfectly. My sorted array will be something like this.
Col 1
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11

duplicate, see: http://forums.ni.com/ni/board/message?board.id=170&thread.id=317581&jump=true
LabVIEW Champion . Do more with less code and in less time .

Sort String Array by Date

I use the following code to populate a string array:
File dirFile = new File("C:\\somedir");
String fileImport[] = dirFile.list();
This gives me a string array with a whole bunch of files in the following format:
XXXDDMMYYHHMISS.xml
What I need to know is what is the easiest way to sort this array based on this date format, or any date format, in the ascending order, so that when I am loading my XML files, I get the oldest one first.
Appreciate any input.
Sam

Use the String name of the file (the Date part), together with a java.text.SimpleDateFormat object to parse() the String. You have to set the formatter with a pattern - these are explained fully in the Javadocs for the SimpleDateFormat class. After parsing, you will have java.util.Date objects for each of the files - you can then use these as keys in a java.util.SortedMap (the values would be the files) - the natural ordering of dates will ensure that they are ordered appropriately

Sorting string array

Hi.
I need a little SORT help.
I would like to sort "f1". The file names is like this:
number_1, number_2 ect.
Can anybody tell me how.
public String [] getFileList() {
String [] f1;
File f = new File(fpath);
f1 = f.list();
return f1;
Best regards
Soren

Easy solution: change your naming scheme to be 2 or 3 digits (if possible)
ie
pic_01, pic_02 ... pic_09, pic_10
Then the natural order of strings will take care of it for you.
If you have more than 100 pics, you would have to do pic_001, pic_002... which would take you up to 1000.
The not so easy solution:
write your own java.util.Comparator to do the sorting.
Heres an example, but it can easily break.
It assumes that the format of the string is text_number and sorts accordingly.
It will break if the strings don't end with _xxx
Comparator picStringComparator = new Comparator() {
     public int compare(Object o1, Object o2) {
          String s1 = (String) o1;
          String s2 = (String) o2;
          int index = s1.lastIndexOf("_");
          String s1Prefix = s1.substring(0, index);
          int s1Number = Integer.parseInt(s1.substring(index + 1));
          index = s2.lastIndexOf("_");
          String s2Prefix = s2.substring(0, index);
          int s2Number = Integer.parseInt(s2.substring(index + 1));
          if (!s1Prefix.equals(s2Prefix)) {
               return s1Prefix.compareTo(s2Prefix);
          else {
               return s1Number > s2Number ? 1 : s1Number < s2Number ? -1 : 0;
Arrays.sort(f1, picComparator);

Simpler way to sort 2-d string array?

I have a long 2d string array, and I would like to sort by the 2nd value. It originates as:
    public static final String names[][] = {
     {"000000", "Black"},
     {"000080", "Navy Blue"},
     {"0000C8", "Dark Blue"},
     {"0000FF", "Blue"},
        {"000741", "Stratos"},
     {"FFFFF0", "Ivory"},
     {"FFFFFF", "White"}
    };As you can see, they are pre-sorted by the hex values. That is useful for part of the app.
There are 1,567 entries. I would like to alphabetize the color names and place them in a list widget. I need to keep the associated hex color values with the name values. All I can think of to do something like:
1) make a temporary long 1-d string array
2) fill it by loop that appends the hex values to the name values: temp[i] = new String (names[1] + names[i][0])
3) sort temp[] with built in Java sort
4) make a permanent new string array, hexValues[] for the hex values
5) copy the last 6 characters of each item to hexValues[]
6) truncate the last 6 characters of each item in temp[]
7) build list widget with temp[]
Is there a more elegant way? What I'd really like to do is build a 1-d array of int's, with the values representing the alphabetized locations of the names. However, I don't see any built-in which would do that kind of indirect sort.
Second question -- Can the backgrounds of each item in a list widget be a different color? Ideally the list would show the color name in black or white, and the its color value as background. Specifically, I'm trying to build the list accomplished by the Javascript code here:
* http://chir.ag/projects/name-that-color/
and add it to my Java interactive color wheel:
* http://r0k.us/graphics/SIHwheel.html
BTW, I have converted his name that color Javascript (ntc.js) to a native Java class. It is freely distributable, and I host it here:
* http://r0k.us/source/ntc.java
-- Rich
Edited by: RichF on Oct 7, 2010 7:04 PM
Silly forum software; I can't see what made it go italic at the word new.

I am implementing a sort infrastructure along the lines of camickr's working example, above. Part of my problem is that I am new to both lists and collections. I've tried searching, and I cannot figure out why the compiler doesn't like my "new":
public class colorName implements Comparable<colorName>
    String     name, hex;
    int          hsi;
    static List<colorName> colorNames;
    public colorName(String name, String hex)
     float     hsb[] = {0f, 0f, 0f};
     int     rgb[] = {0, 0, 0};
     int     h, s, b;     // b for brightness, same as i
     this.name = name;
     this.hex = hex;
     // Now we need to calculate hsi,
     this.hsi = (h << 10) + (s << 6) + b; // hhhhhhssssiiiiii
    ***   findColorName() performs 3 functions. First, it
    *** will auto-initialize itself if necessary. Second,
    *** it will perform 3 sorts:
    ***   -3) byHSI: sort by HSI and return first element of sorted list
    ***   -2) byNAME: sort by name and return first element of list
    ***   -1) byHEX: (re)reads ntc.names, which is already sorted by HEX;
    ***               returns first element of list
    *** Third, on 0 or greater, will return the nth element of list
    *** Note: ntc.init() need not have been called.
    public colorName findColorName(int which)
     if (which < -3) which = -3;
     if (which >= ntc.names.length) which = ntc.names.length - 1;
     if (which == -1) colorNames = null;     // free up for garbage collection
     if (colorNames == null)
     {   // (re)create list
         colorNames = new ArrayList<colorName>(ntc.names.length);
         for (int i = 0; i < ntc.names.length; i++)
             colorNames.add(new colorName(ntc.names[1], ntc.names[0]));
        if (which == -1) return(colorNames.get(0));
}On compilation, I receive:
D:\progming\java\ntc>javac colorName.java
colorName.java:117: cannot find symbol
symbol : constructor colorName(java.lang.String[],java.lang.String[])
location: class colorName
                colorNames.add(new colorName(ntc.names[1], ntc.names[0]));
                               ^
1 errorLine 117 is the second-to-last executable line in code block. I know it is finding the ntc.names[][] array the ntc.class file. I had forgotten to compile ntc.java, and there were other errors, such as in line 115 where it couldn't find ntc.names.length. Compare camickr's two lines:
          List<Person> people = new ArrayList<Person>();
          people.add( new Person("Homer", 38) );As far as I can tell, I'm doing exactly the same thing. If you have any other feedback, feel free to make it. The full source may be found at:
* http://r0k.us/rock/Junk/colorName.java
PS1: I know I don't need the parenthesis in my return's. It's an old habit, and they look funny to me without them.
PS2: My original design had the "static List<colorName> colorNames;" line defined within the findColorName() method. The compiler did not like that; it appears to be that one cannot have static variables within methods. Anyway, that's why I don't have separate sorting and getting methods. I'm learning; "static" does not mean, "keep this baby around". Its meaning is, "there is only one of these babies per class".
-- Rich

Doubt in working of Arrays.sort method. help needed !!!!

Hello Friends,
I am not able to understand output of Arrays.sort method. Here is the detail of problem
I wrote one program :
public static void main(String[] args) throws ClassNotFoundException
     Object[] a = new Object[10];
     a[0] = new String("1");
     a[1] = new String("2");
     a[2] = new String("4");
     a[3] = new String("3");
     a[4] = new String("5");
     a[5] = new String("20");
     a[6] = new String("6");
     a[7] = new String("9");
     a[8] = new String("7");
     a[9] = new String("8");
/* Sort entire array.*/
     Arrays.sort(a);
     for (int i = 0; i < a.length; i++)
     System.out.println(a);
and output is :
1
2
20
3
4
5
6
7
8
9
Question : Does this output is correct? If yes then on which basis api sort an array? I assume output should be 1 2 3 4 5 6 7 8 9 20.
Can here any one please explain this?
Thanks in advance.
Regards,
Rajesh Rathod

jverd wrote:
"20" and "3" are not numbers. They are strings, and "20" < "3" is exactly the same as "BA" < "C"The above is
... quote 20 quote less than quote 3 quote...
but shows up as
... quote 20 quote less than quote...
Weird.

String array into formula node

Hello,
I am taking data from SQL, I am getting multiple rows of data for many different devices. I would like to wire the data into a formula node so I can sepearate and sort via script. However, I am getting an error for "Polymorphic terminal cannot accept this data type". Is there a work around? Can I not wire in a string array to a formula node.
/r
Travo

There are lots of basic string VIs that you can use to parse the string and separate out the individual fields. I would recommend "programming" your application using script nodes. Use the native language. LabVIEW is a fully functional and capable programming language.
Mark Yedinak
"Does anyone know where the love of God goes when the waves turn the minutes to hours?"
Wreck of the Edmund Fitzgerald - Gordon Lightfoot

Large string array in 6.1 is extremely slow

Good day all,
While this is in to tech support at NI, I wanted to see if anyone else has encountered it.
I am upgrading from 6.0.2 to 6.1. Several large (2500 rows by 250 columns or larger) string arrays are used as inputs into subvi's. Under 6.0.2, these functions run in tenths of seconds, while under the converted 6.1 vi's they run in 20 seconds or more!
Tracing back using probes, the problem is occurring at the point of the input. It is appears that the array is taking many seconds to copy from the input to the wire on the diagram.
Array controls generated in 6.1 (not converted from 6.0.2) seem to function just fine. Using a save with options... to convert back to 6.0.2, the vi's again function in tenths of
seconds.
Anyone have any ideas?
Thanks!

I hear what you're saying about legacy code...
Something you might want to be looking at for the future is migrating to a structure where the data is stored in a 1D array, where each element is a cluster contain the data that's now in a single row. This would be the most straight-forward change, but could make getting at the data tricky, depending on how you need to be able to search it.
Alternately, you could have a cluster containing arrays of each of the row values.In this structure element 0 of all the arrays is the first "row", element 1 of the arrays is the second "row" and so on. This structure at first blush looks more complicated, but it's really not, plus it would allow you to use any value (or combination of
values) to search for a specific row without a lot of parsing.
If the data that is in the example VIs you posted is typical, either of these changes would be advantagous because it looks like there is a lot of reptative data that might be able to be encoded in an enum. Plus storing numbers as numbers often reduces the memory required and produces a predictable memory footprint (an I32 will always take-up 4 bytes per value regardless of how large of small the number is). My sense is that the variability of the string size is what's killing you.
One thing that would make this sort of dramatic change somewhat easier is that because you are changing the basic datatype of the interface, you aren't going to have to worry about finding all the places the change will effect--the wires will be broken.
If you ever decide to take this on, give a hollar.
Mike...
Certified Professional Instructor
Certified LabVIEW Architect
LabVIEW Champion
"... after all, He's not a tame lion..."
Be thinking ahead and mark your dance card for NI Week 2015 now: TS 6139 - Object Oriented First Steps

String array operations

Hello. I am trying to implement a method which receives a string array called SCREEN and a string called DITHERED.
I want to check how many CHARS from DITHERED are in SCREEN.
When I try to compile I get "An illegalaccess exception ocurred. Make sure your method is declared to be public". Any help? THANKS
class ImageDithering
    public int count(String dithered, String[] screen)
        int num=0;
        for(int i=0;i<screen.length;i++)
            for(int j=0;j<screen.length();j++)
for(int k=0;k<dithered.length();k++)
if(screen[i].charAt(j)==dithered.charAt(k))
num++;
break;
return num;
}Edited by: devesa on Aug 5, 2010 9:38 AM

devesa wrote:
Hello. I am trying to implement a method which receives a string array called SCREEN and a string called DITHERED.
I want to check how many CHARS from DITHERED are in SCREEN.Well, the method you've chosen is just about as slow as it can be.
A few questions:
1. Which has more characters: 'dithers' or 'screen'?
2. Do you know about StringBuilder?
3. Do you know about [String.indexOf()|http://download.oracle.com/javase/6/docs/api/java/lang/String.html#indexOf%28int%29]?
4. Have you thought about sorting your strings first?
Winston

Array.sort() question

I've been looking at Arrays and the Comparator interface. But I don't understand the sorting results:
import java.util.*;
import java.io.*;
class SearchObjArray {
     public static void main(String[] args) {
          Console con=System.console();
          if (con==null) System.exit(1);
          String[] sa={"one","two","three","four"};
          Arrays.sort(sa);
          con.format("The sorted string:%n");
          for(String s: sa)
               con.format("%s ",s);
          //four,one,three,two
          con.format("%nA binary search for \"one\": one=%s%n",Arrays.binarySearch(sa,"one"));
          //one=1, as expected. The binarySearch found "one" in position 1 of the sorted array.
          ReSortComparator rs=new ReSortComparator();
          con.format("A binary search for \"one\" using the resort comparator on the string array: one=%s%n",Arrays.binarySearch(sa,"one",rs));
          //one=-1<====WHY -1? Why is the insertion point 0?
     static class ReSortComparator implements Comparator<String> {
          public int compare(String a, String b) {
               return b.compareTo(a);


You have to search using the same ordering rules as how the array is sorted. You sorted with one set of rules (String's natural ordering) and searched with a different set of rules (the opposite ordering, as determined by your comparator). That's the same as trying to do a binary search on an unsorted array. Since one of the preconditions of binary search is that the array be sorted, it shouldn't be surprising that you get odd results.

Two dimension string array in teststand

Hello,
I want to pass a two dimension string array from a labWindows dll into Teststand. My labwindows dll:
#define NR_columns 12
#define NR_rows 1200
#define NR_hight 1024
int__declspec(dllexport) __stdcall sort( char pspec[NR_columns][NR_rows][NR_hight])
The call of the dll in teststand looks like the attached picture in the doc file.
and I got the error message which shows the attached second picture in the doc file
what is the problem?
regards
samuel
Attachments:
Error1.doc ‏94 KB

Hello Samuel,
I'm not experienced in LabWindows but I think the reason for this Error is the dimension of FileGlobals.loadspec in TestStand. The Error Dialog displays for this String Array [0..11][0..1200]. That's an array of 12 and 1201 elements but function is expecting 12 and 1200 elements.
I hope this helps.
Kind regards
C. Dietz
Test Engineering
digades GmbH
www.digades.com

Array sort with objects?

hits = searcher.search(query);
//java.util.Vector sortHits = new java.util.Vector ();
int[][] sortHits = new int[hits.length()][1];
// assign values to array
int teller = 0;
for (int i = 0; i < hits.length(); i++)
     Document doc = hits.doc(i);
     String absnumtxt = doc.get("absnumtxt");
     if(sAllCookies.indexOf(absnumtxt) >= 0){
          sortHits[0] = Integer.parseInt(absnumtxt);
          teller++;
          continue;
But the method Arrays.sort(sortHits); causes a ClassCastException error. Somebody an idea to solve this?
The structure is:
sortHits[0][0] = 2
sortHits[1][0] = 0
sortHits[2][0] = 0
sortHits[3][0] = 0
sortHits[4][0] = 0
sortHits[5][0] = 0

A two-dimentional array is an array of array of something.
Sorting a two-dimentional array requires a Comparator, because you compare uni-dimentional arrays, and arrays are not naturally comparable.
(BTW, why declaring a two-dimentional array here? you set the second dimention length to 1... a simple array would make it, no?)

String Array Sorting

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