Row operation on array with a For Loop

Hi,
I'm working with a large one dimensional column array. I'm trying to do the following
for i=1:size(A)/2
B(i,: ) =A(1+(i-1)*2:i*2)
So, for example if
A=
0
1
2
3
4
5
6
7
then
B=
0 1
2 3
4 5
6 7
My approach was to use an array subset block inside the for loop to select a number of elements but I'm not sure how to transpose the selected elements into a new row to create the new array B. Is there a more straightforward approach?
Thanks,
Mike
Solved!
Go to Solution.

try experimenting with the reshape array feeding it your input array and re-sizing it to output a 2d aray. It is much faster than using a For loop becuase the data never gets moved and LV just changes the array dimensions and updates the stride.
Ben
Ben Rayner
I am currently active on.. MainStream Preppers
Rayner's Ridge is under construction

Similar Messages

How to traverse an array with a for-loop in this certain way...

so I need to traverse an array starting from the first element, then from the last element, then the second element, then the second last element, then third element and so on... in a for loop
how would that look in code?
Any help would be appreciated, thanks!
Edited by: inspiredone on Apr 4, 2008 6:34 AM

Wow, that's a really clever and elegant way to do it promethuzz. I actually came up with something already before I read your post so yeah don't worry about me copying or anything. Mine is not as elegant/efficient and I definitely like yours a lot more but I will just share it anyway...it looks pretty similar to the second algorithm The_Matrix has provided. I figured this out from thinking how quicksort compares its pivot with the two indexes...
    int front=0;
    int back = a.length - 1;
    int counter =0;
    boolean switchflag = true;
    while(front<=back)
      System.out.println(a[counter]);
      if(switchflag)
        counter = back;
        front++;
        switchflag = false;
      else
        counter = front;
        back--;
        switchflag = true;
    } Anyways, thanks a lot for you guys help, promethuzz, The_Matrix, and newark.
Edited by: inspiredone on Apr 4, 2008 11:25 AM
Edited by: inspiredone on Apr 4, 2008 11:27 AM

I need help with my for loop in this array

Ok well, I can't get my code to work. Also, please remember that this is just my draft so it isnt pretty. I will fix it up later so please look at it. The thing I want to do is look into the array for a time that matches what the user entered and return the toString() of that one. I know there is something wrong with my for loop but I cant figure how to fix it. please help. here is what i have so far:
import javax.swing.JOptionPane;
public class Runner
    public static void main (String[] args)
        String timeStr;
        int time, again, optiStr;
        Inbound[] in = new Inbound[25];
         in[0]=new Inbound ("",0,"On Time num0");
         in[1]=new Inbound ("",2,"On Time num1");
         in[2]=new Inbound ("",3,"Delayed num2");
         in[3]=new Inbound ("",4,"On Time");
         in[4]=new Inbound ("",5,"On Time");
         in[5]=new Inbound ("",6,"Canceled");
         in[6]=new Inbound ("",1,"Canceled num6");
         in[7]=new Inbound ("",8,"On Time");
         in[8]=new Inbound ("",9,"Delayed");
         in[9]=new Inbound ("",10,"On Time");
         in[10]=new Inbound ("",11,"Delayed");
         in[11]=new Inbound ("",12,"On Time");
         in[12]=new Inbound ("",13,"Delayed");
         in[13]=new Inbound ("",14,"On Time");
         in[14]=new Inbound ("",15,"On Time");
         in[15]=new Inbound ("",16,"On Time");
         in[16]=new Inbound ("",17,"Canceled");
         in[17]=new Inbound ("",18,"On Time");
         in[18]=new Inbound ("",19,"On Time");
         in[19]=new Inbound ("",20,"Canceled");
         in[20]=new Inbound ("",21,"On Time");
         in[21]=new Inbound ("",22,"Delayed");
         in[22]=new Inbound ("",23,"On Time");
         in[23]=new Inbound ("",24,"Cancled");
         in[24]=new Inbound ("",7,"On Time num24");
        do{
            timeStr = JOptionPane.showInputDialog ("In military time, what hour do you want?");
            time = Integer.parseInt(timeStr);
            if (time<=0 || time>24)
             JOptionPane.showMessageDialog (null, "Error");
             optiStr = JOptionPane.showConfirmDialog (null, "If you want Incoming flights click Yes, but if not click No");
            if (optiStr==JOptionPane.YES_OPTION)
//(ok this is the for loop i am talking about )
                for (int index = 0; index < in.length; index++)
                  if ( time == Inbound.getTime())
               JOptionPane.showMessageDialog (null, Inbound.tostring()); //return the time asked for
//               else JOptionPane.showMessageDialog (null, "else");
            }//temp return else if failed to find time asked for
//             else
//               if (optiStr==JOptionPane.CANCEL_OPTION)
//                 JOptionPane.showMessageDialog(null,"Canceled");
//              else
//                {Outbound.run();
//                JOptionPane.showMessageDialog (null, "outbound");}//temp
              again=JOptionPane.showConfirmDialog(null, "Try again?");
        while (again==JOptionPane.YES_OPTION);
}any help would be greatly appriciated.

rumble14 wrote:
Ok well, I can't get my code to work. Also, please remember that this is just my draft so it isnt pretty. I will fix it up later so please look at it. The thing I want to do is look into the array for a time that matches what the user entered and return the toString() of that one. I know there is something wrong with my for loop but I cant figure how to fix it. please help. here is what i have so far:
>//(ok this is the for loop i am talking about )
for (int index = 0; index < in.length; index++)
if ( time == Inbound.getTime())
JOptionPane.showMessageDialog (null, Inbound.tostring()); //return the time asked for
Inbound.getTime() is a static method of your Inbound class, that always returns the same value, I presume? As opposed to each of the 25 members of your array in, which have individual values?
Edited by: darb on Mar 26, 2008 11:12 AM

Issues with nested for loops - saving images from a camera

Hi all,
I've written a vi. to capture a specific number of images ('Image No') and save these images, outputted to a folder of my choice. Each image is identified sequentially. However, I wish to do a number of iterations ('Run') of this capture sequence, such that the filename of each image would be 'Filename (Run)_(Image No).png', e.g. run 5, image 10 would be 'Filename 5_10.png'. I have tried a nested for loop for this but I receive an error 'Asynchronous I/O operation in progress' (I've attached a printscreen).
Can anyone assist me in solving this problem? I preiously posted this in machine Vision but got no response (http://forums.ni.com/t5/Machine-Vision/Capturing-image-sequences-issues-with-nested-for-loops/m-p/19...). Please find attached my vi.
Kindest regards and thanks,
Miika
Solved!
Go to Solution.
Attachments:
Labview problem.jpg ‏3841 KB
Image sequence save to file.vi ‏48 KB

Miika,
the problem is not the filenam, but the name of the folder (AHHHHH!). You try to create the same folder in the outer for loop over and over again.... (it is the error message above the '======', not below )
Norbert
CEO: What exactly is stopping us from doing this?
Expert: Geometry
Marketing Manager: Just ignore it.

Truncating an array within a for loop

I'm currently working with a program that builds an array of 3000*N real numbers, where N is a control that I specify. I want to pass this array into a for loop that runs N times, each time splitting the first 3000 numbers of the array. So, in other words I want the for loop to execute enough times such that the initial array will be completely divided into groups of 3000 when I'm finished. Later I'll be finding the maximum value of all of these subarrays and taking the average of those. What I tried first is to pass the array into the for loop, then truncate it at index = 3000, but the problem is that I can't hard code the loop to do this N times. Any advice or other methods you'd recommend for doing this?
Thanks.
Message Edited by Robtn on 03-05-2010 03:17 PM

Mark--I don't think I can use that approach. Let me be more specific on what the problem is:
Our "big program" is a giant while loop that constantly reads in voltage values from a DAQ assistant.
It has two modes, the first of which I'm having a lot of trouble with. This mode uses a for loop (N = 3000) nested within the giant while loop.
When the for loop activates, the DAQ assistant takes reads 300 samples for every iteration and takes the maximum of those 300 values. It then builds an array composed of all the maxima. After the for loop has executed 3000 times, a case structure activates, which then finds the maximum of the array of maxima.
I want this (N=3000) for loop to execute an arbitrary number of times, a number that I will specify. Each of those times it should generate a completely seperate array of maxima. So, if I want the for loop to run 5 times, I want 5 different arrays.
My approach for doing this was to change N=3000 to say N = 15000, then split up the resulting array 5 times. So, I need an entirely separate for loop that reads in this array of 15000 maxima on its own and splits it 5 ways. I think what you're suggesting is to use a for loop outside of the N=3000 loop, which is a good idea in theory, but experience has shown that this will not generate 5 separate arrays. It will actually concatenate each array into one, hence the problem we currently have.
Yik--I won't have access to Labview over the weekend. Is it possible to take a screenshot and post it, or maybe a short description?
Thank you for the responses.

Transposing data in an array using a For Loop

I am trying to transpose some data in an array using a for loop starting from the size of the array then decrement down to 0. Can someone please help if you have an example?
Solved!
Go to Solution.

I feel as if reverse 1D array may help
Edit: misunderstood what your second post meant.
CLA, LabVIEW Versions 2010-2013

Trying to save key strokes with a for loop

I have been trying to action script for years with no
success. I to some time off and learned javascript and some oop
(ruby) so I thought I would take another stab at it. I am still
having problems. Here goes...
I have several movieclips on the stage that will be set up as
buttons. They all have the same effects associated with mouseover
and mouseout so I thought I could save some key strokes with a for
loop. But I can't get it working right. Could someone tell me what
I am doing wrong please?
If anyone can help it would be appreciated.

kglad,
Thanks for taking a look. In answer to your question. The
movie clip instance names are mc_ItemText0 ... mc_ItemText3.
quote:
those declarations at the top of your for-loop aren't doing
anything useful. what are the names of you movieclips that are
on-stage?
In reg\ards to the variable declarations, sorry my variable
names are causing confusion. I use the name "mc" for two different
variables. Once for the FOR loop and a separate time locally in the
functions grow and shrink. The ones set for the For loop are used
in the 'onEvents' at the bottom of the script. Sorry for the
confusion.
Because the code works if I take it out of the FOR loop and
replace the
's with the numbers that corruspond to the movie clip; I don't
think the similar names are conflicting because of the scope. To
make the code more readable and eliminate confusion I have posted
the code with unique variable names.
I have searched the forum for FOR loop difficulties and
found several cases that seemed similar to mine, but I didn't
understand what was happening.
Examples:
http://www.adobe.com/cfusion/webforums/forum/messageview.cfm?forumid=15&catid=288&threadid =1253110&highlight_key=y&keyword1=for%20loop
http://www.adobe.com/cfusion/webforums/forum/messageview.cfm?forumid=15&catid=288&threadid =1202338&highlight_key=y&keyword1=for%20loop
My code with unique variable names to end confusion:

The demand of my application is that i can not replace for loop with a while loop.because i need fixed number of iterations and as far as i know fixed iterations could be only with possible with the for loop.

the demand of my application is that i can not replace for loop with a while loop.because i need fixed number of iterations and as far as i know fixed iterations could be only with possible with the for loop.
your recommended second option that i could add true/false case.
this true/false case must be inside the for loop or outside the for loop?if this case is inside the for
loop, how can i send stop command from outer while
loop?
more over do you have any example for this please?
thanks"

You can execute a fixed number of iterations using a while loop by comparing the iteration count to the number of iterations you want and wiring the output of that comparison (e.g. Less Than or Equal To) to the continue (or stop) terminal of your while loop. Which comparison you use depends on personal preference, where you wire the desired count and the interation count, and whether you're using the while loop as Continue if True or Stop if True.
Ben gave you step-by-step instructions in response to your previous question. Look here for Ben's response.
Ben's response looks pretty good and detailed to me. It certa
inly deserved better than a 1-star rating.

Please help with the FOR loop and the array..

I was trying to place some words in the Movie Clip
"TextPanel" and set a
random position to each of them.
But it's not working.
1) I created a Movie Clip "word" and inside that MC I created
a text field
and gave it an identifier "textFiled".
2) The linkage name for Movie Clip "word" I set to "word".
3) In the actionscript I created an Array called "aWords".
4) Then I created a FOR loop that should
place (attach) Movie Clips "word0", "word1", "word2" and
"word3" to the
movie clip TextPanel, and set the textField text for each of
them to the
text from the Array.
But the script attaches 4 Movie Clips with a name
"Undefined", instead of 4
different names (from the Array).
What is wrong with this script?
var aWords:Array = [apple,banana,orange,mango];
for(i=0;i<aWords.length;i++){
var v = TextPanel.attachMovie("word","word"+i,i);
v.textFiled.text = aWords
v._x = randomNumber(0,Stage.width);
v._y = randomNumber(0,Stage.height);
Thanks in advance

But in my Post I already wrote v.textFiled.text = aWords
so I don't understand what were you correcting..
And one more:
I have tested it by changing the
v.textFiled.text = aWords; to v.textFiled.text = "some
word";
and it's working fine.
So there is something wrong with the Array element, and I
don't know why..
"aniebel" <[email protected]> wrote in
message
news:ft2d5k$lld$[email protected]..
> Change:
> v.textFiled.text = aWords;
>
> to:
> v.textFiled.text = aWords
>
> It needs to know which element inside the array you want
to place in the
> textfield (or textfiled) :)
>
> If that doesn't work, double check that your instance
name is correct
> inside
> of "word".
>

Help with a FOR loop and an object array

I need to make a for loop that takes an array of objects that contain the parameters year, type, and model (all ints) and sort by year, then divide the array in all the objects with the same year and sort them by type, then divide the array again into the objects with the same year AND type and sort them by model.
the object a Dress objects, the get methods are get+nameof parameter.
the array is a 1D array called Dresses.
I have made a paralell array to store the value of the parameters and sort that then move the array acording to that sorted array. The problem is in the division of the array.

We'll give your request to do (or finish) your homework for you the attention it deserves.

Array building with a for loop

I am using indexing on the right edge of a For Loop to try to build a larger 2-D array out of smaller 2-D arrays but the output of the tunnel insists on being a 3-D array. I will attach my VI. The sub VIs are not important; the comments in the block diagram should explain the situation sufficiently. Thanks!
Attachments:
Loop_array_example.vi ‏24 KB

Please disregard this request for help. I solved my problem by using 'insert into array' instead of building array.

Methods to build an array inside a For Loop.

Let me introduce to you my nested For Loops:
They output a 2D boolean array depending on two 1D boolean arrays of different lengths. This is all well and good however, in another part of my program, I want this to be a 1D array instead.
Idea #1:
"I'll just reshape the array at the end. Simples!"
Idea #2:
"Hang on, why am I using three primitives outside the loop when I can use just one inside it along with a shift register?"
Idea #2.5:
"Oh, wait... I remember reading somewhere about continuously building an array (with concatenate inputs) inside a loop being a bad thing and quite slow. Let me test this."
Spoiler (Highlight to read)
Idea #3:
"Umm... okay, so actually the second way is faster. I think if I initialize the shift register first then replace subsets of the array, that might also be better."
Spoiler (Highlight to read)
Idea #4:
"Yep - seems much better. (Something to do with LabVIEW not having to constantly allocate more memory on every iteration of the loop) Looking at this closer, I don't actually need the inner For Loop because of the way I'm handling the arrays. Try again...!"
Spoiler (Highlight to read)
Conclusion(?) #1:
"Well I seem to have arrived at something that looks messier, but executes about 6x faster than my initial idea. That said, the difference rapidly increases as the input arrays get much bigger (becoming orders of magnitude different)."
Is this the most efficient way of doing what I want? Or is there something even better (and works in LV 8.5)?
Never say "Oops." Always say "Ah, interesting!"

Thank you both for the feedback. It never occurred for me to recheck the logic after I'd initially extracted the nested For Loops, but the AND gate output is obviously the same now that it's been pointed out!
Continuing on with Idea #4, I replaced the Select with an AND then compared the times. (also meant I didn't have to initialize one of the arrays anymore)
Spoiler (Highlight to read)
It appears that the AND gate was slower but then I tried with different sizes of initial arrays and in one case, the timings were 'reversed'.
This only happened when the top array (the one that is fed into the AND gate whole) was reduced to a length in the region of 5 elements long.
Spoiler (Highlight to read)
Why does this happen? Is it something to do with the AND gate possibly being optimised for single element operations so smaller arrays are handled better...?
Never say "Oops." Always say "Ah, interesting!"

Multidimensional arrays with enhanced for statement

hello, do you know if it is possible to use enhanced for loop with multidimensional arrays, and if yes, then how?
for example:
int[][] arr = {{1,2},{3,4}};
for(int i[][] : arr){
    doSomethingWith(i[][]);
}

The syntax is nice'n'easy:
void f(int[][] m) {
    for(int[] row : m) {
        for(int x : row) {
}

Passing an array in a for loop to a procedure

I am trying to pass an array in a cursor for loop to a procedure which performs a table insert using the array's contents. Somehow I am missing something, or it is not possible. The compile error states: PLS-00306: wrong number or types in call to 'insert_address' I checked to be sure I am creating the arrays in both cases from similar data objects. Both address and work_address_table contain the same 4 columns with the same data types.
create or replace package work_address as
FUNCTION populate_address return boolean;
procedure insert_address(in_address IN work_address_table%ROWTYPE);
end work_address;
create or replace package body work_address as
function populate_address return boolean is
cursor c1 is
select 'H' as header,
street1 as street
city as city,
NULL as state
from address
where city = 'HANOVER';
TYPE addressT IS TABLE OF c1%ROWTYPE INDEX BY BINARY_INTEGER;
rec1 addressT;
BEGIN
OPEN c1;
FETCH c1 BULK COLLECT INTO rec1 LIMIT 500;
FOR i IN 1..rec1.count LOOP
rec1(i).state := 'US'
insert_address(rec1(i));
exit when c1%notfound;
END LOOP;
CLOSE c1;
return TRUE;
END populate_address;
PROCEDURE insert_address(in_address IN work_address_table%ROWTYPE) IS
BEGIN
INSERT INTO work_address_table
VALUES (in_address.header,
in_address.street,
in_address.city,
in_address.state);
COMMIT;
END insert_address;
END work address;
/

Both address and work_address_table contain the same 4 columns with the same data types.Are you 100% sure about this?
SQL> declare
cursor c1
is
    select 1 deptno, dummy dname, 'Loc' location from dual;
type addresst is table of c1%rowtype
    index by binary_integer;
rec1   addresst;
procedure p (d dept%rowtype)
as
begin
    dbms_output.put_line(d.dname);
end p;
begin
rec1 (1).dname := 'z';
p (rec1 (1));
end;
z
PL/SQL procedure successfully completed.but changing just the first column of the cursor:
SQL> declare
cursor c1
is
    select 'xy' deptno, dummy dname, 'Loc' location from dual;
type addresst is table of c1%rowtype
    index by binary_integer;
rec1   addresst;
procedure p (d dept%rowtype)
as
begin
    dbms_output.put_line(d.dname);
end p;
begin
rec1 (1).dname := 'z';
p (rec1 (1));
end;
Error at line 3
ORA-06550: line 20, column 3:
PLS-00306: wrong number or types of arguments in call to 'P'
ORA-06550: line 20, column 3:
PL/SQL: Statement ignored

Problem cycling through elements of an array using a for loop ~ error 200609?

Hi,
I'm outputting a 194-element array from a MATLAB script node into a for loop where the array is indexed then converted into a 8-bit boolean pattern which I'm trying to output using DAQ Assistant. I'm using LabVIEW 8.2 and a PCI 6133 DAQ using a counter(Ctr0InternalOutput) to time the output. The first element of the array goes through the loop perfectly however never makes it's way back through and throws error 200609: Generation cannot be started because the slescted buffer size is too small. Increase the buffer size. After probing the line before DAQ Assistant I confirmed only one element makes it through the loop and then throws this error? I've trying doing the same things with lower lowel DAQmx vi's using a DAQmx configure output buffer vi to override this buffer size problem, but still get the same result(not the error but same data flow problem)? Anybody know what's going on? I've included the vi's I've been working with. Thanks!
Millie
Attachments:
Untitled 22.vi ‏228 KB
Untitled 34.vi ‏180 KB

Hi,
I'm outputting a 194-element array from a MATLAB script node into a for loop where the array is indexed then converted into a 8-bit boolean pattern which I'm trying to output using DAQ Assistant. I'm using LabVIEW 8.2 and a PCI 6133 DAQ using a counter(Ctr0InternalOutput) to time the output. The first element of the array goes through the loop perfectly however never makes it's way back through and throws error 200609: Generation cannot be started because the slescted buffer size is too small. Increase the buffer size. After probing the line before DAQ Assistant I confirmed only one element makes it through the loop and then throws this error? I've trying doing the same things with lower lowel DAQmx vi's using a DAQmx configure output buffer vi to override this buffer size problem, but still get the same result(not the error but same data flow problem)? Anybody know what's going on? I've included the vi's I've been working with. Thanks!
Millie
Attachments:
Untitled 22.vi ‏228 KB
Untitled 34.vi ‏180 KB

Row operation on array with a For Loop

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