How to sort a 2 dim Array ?

hello
I would like to sort a 2-dim array of double ( double[][])
according to the 1st column
It is possible to sort a 1st dim array (doubel[]) , but the method sort
of the class Array doesn't work with double[][]).
I have two (bad) solutions.
1) Writing a sorting method but I would prefer using the sort' method of java which uses quicksort
2) Creating a table of objects that implements Comparable but this would decrease performance
Do you have a better Idea ?
Thanks a lot

I would like to sort a 2-dim array of double (double[][]) according to the 1st column
Which is the first "column"? double[0][x] or
double[x][0]?
If it's the second one things get simple: your
double[][] is really an array of objects where each
object is an array of doubles. So all you need to do
is write a custom Comparator for double[] to use the
sort method:
compare(Object obj1, Object obj2) {
double[] d1 = (double[]) obj1;
double[] d2 = (double[]) obj2;
return d1[0] > d2[0];
}Thanks for your so prompt answer.
I can manage to put the data so that I sort the array according to x as in double[x][0]?
But WHERE do I have to write the "compare" method ?
Thanks

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How to sort a 2 dim. array by the first column?

Hi there,
I need to know, how to sort a 2 dim. String array by the first column, which means "string[0][x]".
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I need to know, how to sort a 2 dim. String
array by the first column, which means
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Let's forget about generics. Say you want to supply a Comparator. The compare method should decide the order between elements when passed two element objects. In a two-dimensional array the elements will be one-dimentional arrays and you use the first element in those arrays, like
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Sort a 2-dim array?

Hello!
Now we have the following problem: We need to sort a 2-dim array depending on the values in the first column. Then we need the corresponding row to move to the right place too... we send a VI so you can see an example of how it might look like. So we need (in this case) the first column to sort so we get 1,2 and 3 and so on, so the last row should be 3,4, 392 and 2047.
We think this might be easy to solve but we need some tip :-) Thank you and best regards.
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sortarray.vi ‏17 KB

I wrote my own 2D string array sort routine. It has come in handy many times. You can enter the column number that you want to sort on, and the entire rows are rearranged in the order of the column sort. If your array is numeric, you can easily change the vi to use numerics instead. One day I hope to make it polymorphic. Here it is:
- tbob
Inventor of the WORM Global
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Sort2DArray(str).vi ‏63 KB

How do I find the total number of elements in a multi dim array

How do I find the total number of elements in a single or multi dim array?
For example, a 2x3 array has 6 elements, and a 2x3x4 has 24. How do I compute this very easily - is there a single VI that does this?
David
Solved!
Go to Solution.

Use "array size" (array palette) followed by "multiply array elements" (numeric palette)
(Works also equally well for 3D arrays and higher)
For a 1D array, just use "array size".
Message Edited by altenbach on 02-05-2009 05:57 PM
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NumberOfElements.png ‏3 KB

In the attached vi, I have a 2-dim series of EMGs which I would like to connect with a 1-dim array. How can I do this?

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Hi,
can you post your curve fitting .vi?
I think you can do this with the reshape array.vi, and take the 2-D array, find out it's size, and multiply the two dimensions together to get the number of elements you need. That'll give you the array as 1-D, but whether it's in the correct order as you need it is another matter.
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// it takes almost no time to rate an answer

How to declare an expandable 2-dim Array

Hi,
How do I declare a 2-dim array that is can expandable with additional data?

Look at this example (Catching the ideas of the other guis:
e.g. create a Class Object which represents a Row
class Row {
ArrayList list = new ArrayList(10); //ten columns
public Object getObject(int x) {
list.get(x);
public void setObject(Object o, int x) {
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Create an Table Object which is able to add your Rows-Objects
class Table {
ArrayList rows = new ArrayList();
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How to fill up a 3-dim array?

Hello!
See the attached vi. We want to fill upp a 3-dim array. The pages are "number". If "true" is true then we want to insert the row that we build inside the case on page number "number". But the problem is that the new element is placed outside the 3-dim array because the pages are not the same size. How can this problem be solved? Maybe we should use "replace element" ? Does anyone have a tip or idea?
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trouble1.vi ‏51 KB

Hello Ex-jobb,
if you want to replace an element of an array, than the index has to be inside that array... Otherwise you have to add an element using build array.
I changed your example a little bit.
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2) Making the array constant "bigger" by setting a values at index [6,6,6]. You can NOT replace anything inside an empty array!
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CLAD, using 2009SP1 + LV2011SP1 + LV2014SP1 on WinXP+Win7+cRIO
Kudos are welcome
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Two dim array

hello
it would be really nice if someone could help me with that.
i am trying to sort an array and i have read that i can do that with a statement called sort(), but it doesn't seem to work.
this is what i have tried:
for(int i = 0; i < arr.length; i++)
       for(int j = 0; j < arr.length; j++)
           sort(arr[i][j]);
}the error i get is:
Exercise5W2.java [56:1] No method found matching sort(int)
sort(arr[i][j]);
^
1 error
thanks for ur help!

You can use the java.util.Arrays.sort() with and without
the java.util.Comparator interface.
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then you sort the whole two-dim array.
Here is how it goes:
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System.out.print(twoDimIntArray[i][j] + " ");
System.out.println();
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class TwoDimIntArrayComparator implements Comparator
public int compare(Object o1, Object o2)
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int[] oneDimIntArray2 = (int[])o2;
// First integer of each array to be different,
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for (int i = 0; i < oneDimIntArray1.length; i++)
if (oneDimIntArray1[i] > oneDimIntArray2[i])
return 1;
else if (oneDimIntArray1[i] < oneDimIntArray2[i])
return -1;
// All integers of the arrays are equal
return 0;
public boolean equals(Object obj)
return false;

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How to sort files by TimeStamp.

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System.arraycopy (2 dim array) and growth of 2 dim array

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} // End ClassI deeply appreciate your help with these 3 questions :
1. How can I use system.arraycopy to copy my two dimensional array? I have searched but examples seem to be about one dim arrays.
2. How can I change the "static Object arrayGrow(Object a)" , to grow my two dimensional array ?
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Thank you
Denis

1. How can I use system.arraycopy to copy my two
dimensional array? I have searched but examples seem
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>
2. How can I change the "static Object
arrayGrow(Object a)" , to grow my two dimensional
array ?Why do you make it so complicated (generic). Make it take an int[][] array instead, and see the answer from above.
>
3. If you know any codes or articles or java code
regarding cartesian products , please tell me.There are probably lots of them if you google.
Kaj

Sorting a two dimensional array

Hello!
I have a twodimensional array that consists of 6 other arrays
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that?
Thanks!

use a custom sort function. check the sort() method of the
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Create a 2-dim array dynamically

Hello!
I have had this problem here before but try one moore time :-)
This is the thing: We have a text-file from which we read. This textfile can be different from time to time. From this textfile we can catch numbers of columns and numbers of rows that a 2-dim array should have. The problem is how one can create this 2-dim array dynamically? We have a while-loop that the program runs inside already. Must one use the while-loop to solve this problem? Or can one solve this with only a for-loop? Hope you understand how I mean :-) Best regards

OK, I thought you want to read an array of the same size as the actual data in the file. You cannot read a 4x10 array if the file only contains data for a 3x5 array .
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LabVIEW Champion . Do more with less code and in less time .

Sorting a 2-D array

Hello Every one,
Can any one please help me out in sorting a 2-D array. Here is the requirement there will be some groups, and each group consists of 'x' number of elements.The user enters only elements but in a zig zag order. And the program short sort out each channel and list out to which group it is belonging (Where the 2-D array of Group name and elements is provided).
Say for example if there are three groups with some elements in each groups as follows.
Physics: retarder, force,torque,capacity
Chemistry: reaction, chemicals, sodium
Geography: land,map,soil, earth.
And if the user enters the following input's: soil, torque, chemical, force,reaction, land.
The program should return the following output:
Note : The order of the elements should match the order they are defined.
Physics, force,torque ------------ group name and group elements in the first row
Chemistry, reaction, chemical ------------ group name and group elements in the Second row
Geography,land, soil ------------ group name and group elements in the third row
Thanks for the help
- Raghu
Solved!
Go to Solution.

Sure Jim, I can definitely share my project details.Here is what we are trying to achieve.
The attached vi is used to transmit the messages to Engine ECM. It takes the input's *.dbc file where the channel names are defined
The present vi is working like this. It transmit messages correctly only if the messages are defined in the ascending order(the order in which they are defined in the *.dbc file).
Say for example take 3 PGNS
1) 18ff0fef Which has the following channels in the PGN
a) Notch
b) Gear
c) Service brake
2) 14ff2ef which has the following channels in the PGN
a) Bus_voltage
b) Bus_current
c) power
3)14ff03ef which has the following channels in the PGN
a) Coolant_temp
b) oil_press
c) Imat
If I want to transmit the following channels and define them in the following order
1) Gear
2) Imat
3) Bus_voltage
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The program is only writing correct data for Gear,Imat and some garbage values for Bus_voltage and Notch.
But if I define the channels in the ascending order as defined in the *.dbc file in the following fashion
1)Notch
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I can transmit the right data for each channel.
So what Iam trying to do is Iam planning to sort out all the channels names what user enter's and sort the channels in the order as defined in the *.dbc file and pass it to the program.
And the other issue I am facing is if two channels belong to the same PGN like Gear and Notch I have to transmit the values in the same array.
Say for example i want to transmit the values as follows Notch =4; Gear = 3; Bus_voltage = 25; Imat = 80 the array matrix will be like this
Array_1: 4,3
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Array_3: 80.
I was able to sort out all the channels listed in the *.dbc file in to single array but have no clue how to do the rest of work. Can you please help me in achieving the expected result. Iam attaching the vi and picture which describes where channel information and channel values are passed to the program.
Thank you,
- Raghu
Attachments:
Output.vi ‏27 KB
TX_GUI.PNG ‏77 KB

How to sort a set of integers

I have an int array containing a set of integers, and an empty ArrayList.
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Do you really need to follow those steps? Or do you just want to end up with a sorted ArrayList?
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How to sort a 2 dim Array ?

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