Using a for loop to populate JButton values with letters of Alphabet

I am trying to create a column of 26 JButtons, with the text of the button being a letter of the alphabet, but I want to find a faster way to do it. I've tried using the Character class, but it won't let me use an int variable with the constructor. The primitive char class won't allow the '++' operand. I was thinking of using the Unicode values, but I haven't figured out a way to use them in a for loop. Any ideas?

Hope this helps :-)
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class CreateButtons {
     private static JPanel ToolPanel;
     final static JFrame ToolFrame = new JFrame("Drawing Tools");
     public static void main(String[] args) {
          ToolPanel = new JPanel(new GridLayout(17, 1));
          ToolPanel.setBorder(BorderFactory.createTitledBorder("Tools"));
          for(int i= 0; i < 26; i++) {
               char c = (char)('a' + i);
               makeButton(c);
          ToolFrame.getContentPane().setLayout(new BorderLayout());
          ToolFrame.getContentPane().add(ToolPanel, BorderLayout.CENTER);
          ToolFrame.setLocation(100, 100);
          ToolFrame.pack();
          ToolFrame.show();
     static public void makeButton(char buttonName){
          JButton button = new JButton( Character.toString(buttonName) );
               button.addActionListener(new ActionListener() {
               public void actionPerformed(ActionEvent e){
                         System.out.println(e.getActionCommand());
     ToolPanel.add( button );
}

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I'm creating an array using a for loop, how do I get the values outside the loop while it is running? thanks

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I tried to create the local variable that was wired to numeric indicator inside the loop. If I try to connect this to the analog output outside the loop, the loop just starts blinking and nothing happens, am I doing something wrong? Thanks again.
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Using a For loop to call one array element at a time

I have been working on a VI that reads a GPS unit, parses the data, outputs what I need, compares the actual GPS location to the desired location, determines a desired heading and moves on from there. My question pertains to the number of desired locations I can input right now. I need to be able to input a predtermined number of locations (not just the one that I can input right now). I was told that it is possible to use a For Loop with an array and have the first set of Lat and Long values run through the VI and when everything is complete that the next set of values will be chosen. Does this mean that I need to put the entire VI inside a For Loop and have the array update as soon as the VI has completed its first mission? I understand the concept of how this work from other programming languages but I'm not sure how to implement the solution in LabVIEW. Any help would be appreciated.
Adam

adamoutlaw wrote:
Here is a portion of the VI. I need two separate arrays, one for Latitude and one for Longitude, of the same size.
I don't see any arrays in your code. Do you want to generate arrays form individual data points or do you want to process arrays, one element at a time? Both can take advantage of autoindexing. Here's a simple picture.
Your VI contains a weird mix of DBL and EXT precision. Most likely all you need is DBL. Keep your representations consistent!
Message Edited by altenbach on 08-02-2007 07:14 AM
LabVIEW Champion . Do more with less code and in less time .
Attachments:
Indexing.png ‏4 KB

Using a For Loop Index for Array Element Number?

Hi. Thanks in advance for the help. I can't seem to find what I want to do here using the search function... probably because I don't know how to frame the question appropriately. Ignore the title to this post cause it's probably wrong vocabulary for what I want to do.
Here's the situation:
I have a 2D array where the first column is the X data and each subsequent column is Y data (call it Y1...Yn). The n-value varies from run to run (some runs have 4 columns of data, some have 20), but that is easily gathered when reading the data file. I need to perform a number of operations on each set of data, the least of which is smoothing the data and graphing it, so I'm limiting my discussion to these 2 operations.
What I want is a for loop structure where the indexing of the loop tracks the Y1...Yn columns, grabs each column for the iteration, performs the relevant analysis, and spits out the result, but in a stackable manner. Thus the title; I want to use the for loop's index to mark the array element for building a new array.
See the image attached. A 2D array of 9 columns (X, Y1...Y8) is analyzed such that each data set, (X, Y1), (X, Y2)...(X, Y8) is bundled, graphed, run through a B-spline Fit, of which is also graphed. I need to replace this with something that looks like the for loop structure shown.
I just don't know how to get those two data bundles [(X, Yi) and it's smoothed pair] out of the for loop in a stacked set from every iteration of the for loop.
Again the title, I think I want to build a new array where i use the index of the for loop to control the entries of the new array. But I can't see how to do that.
Any help would be appreciated.
Attachments:
NeedForLoopForThis.PNG ‏30 KB

Hello H.R. Dunham, and welcome to the forum!
It seems that you may be looking for Auto-Indexing, a basic feature of loops in LabVIEW. You'll need to transpose your array before wiring it into the for loop, as elements are auto-indexed by row before column, but at that point you should be able to operate on each column and output an array of n cluster elements corresponding to your input columns. Auto-indexing tunnels look like brackets to indicate each element will be indexed automatically- this should be the default when wiring an array into a for loop or when wiring anything out of a for loop.
As for how to build your pairs, I suggest removing the X column and creating a "starter" cluster containing your X data and placeholder Y data before entering your "Y" processing loop. Use the bundle by name function in the for loop to insert your processed column data into the cluster and auto-index the cluster output. Flow would be something like this:
1) Gather data
2) Split X and Y using standard array operations
3) Create "template" cluster with shared X data
4) Pass template cluster and Y-column array into an auto-indexed for loop.
5) Insert processed Y data into cluster inside loop.
6) Auto-index cluster data out of loop.
This tutorial is probably also a good place to get started:
Getting Started with NI LabVIEW Module 3: Loops
http://www.ni.com/white-paper/7528/en/
Hope that helps!
Regards,
Tom L.

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

Weird problem with loading data from an XML using a for loop

Hi,
I have a strange problem. I have encountered this thing many a times but still don't know the proper workaround for it.
I am trying to load swf file, a video file or an image. They can be present on a local system or on a remote server also. All the entries corresponding to the files to be loaded is made in an XML file. I traverse through the nodes of the XML using a for loop. On the complete event of loader info, example:.
loader.contentLoaderInfo.addEventListener(Event.COMPLETE, onComplete);
I fill a container with the loaded data.
My problem is when I am using for loop it doesn't works properly but if i use a statement like this:
someFunc()
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All files are loaded properly.
I think this can be because the for loop processes pretty fast but the content takes time to load, which ultimately leads to some wierd results.
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You don't want to use a for loop to load several items. The way you almost appear to have it is the proper approach... load a file and use the completion of its loading to trigger loading the next file.

I would like to use Formcentral form data to populate a pdf with the same fields. Is that possible?

I would like to use Formcentral form data to populate a pdf with the same fields. Is that possible?

Randy,
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Making JButton name a varible for use in for loops

Ok I've got some 98 buttons which are laid out in a grid, and a for loop would work to make thing easier when it came time to make adjustments or changes. Therefore, I would only have to make changes once instead of editing some 196 lines (Making the button, then adding for each button) Both the button names are incremental and their lables
Here is what I got:
// for loops to do the increase of Char Letter and Int Number
String buttonName = "rowButton" + Letter + "" + Number;
JButton buttonName = new JButton( Letter + " " + Number);
// closing of for loop
What do I need to do to make a string value to be the new button's name?

String buttonName = "rowButton" + Letter + "" + Number;
JButton buttonName = new JButton( Letter + " " + Number);
What language allows this? There has to be some language that allows >this, otherwise why do so many people think you can do it in java. Uhmm, actually it works fine in Java. One method to convert an integer to a string is to do:
int i = 10;
String new_string = "" +i;
//new_string == "10"

Can I use a for loop to add anonymous ActionListener objects?

I have a setListener() method that has the following inside:
for(int k = 0; k < buttons.length; k++)
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}I have a JButton array and a Color array and I was hoping I could add them quickly in one shot rather than manually adding an anonymous ActionListener 9 times (I have 9 components). It tells me I need to make k final for an inner class and when I tested it by removing the for loop and keeping k as a final integer, it works. Is there a medium such that I can achieve what I want more or less while respecting Java's syntax?
Any input would be greatly appreciated!
Thanks in advance!

s3a wrote:
The local variable exists on the stack for as long as the method is executing. Once the method ends, that variable no longer exists. The newly created object, however, can continue to exist long after the method has ended. So when it's referring to variable X, it cannot refer to the same X as the one in the method, because that variable may no longer exist.Sorry for picking on little details but I am still not fully satisfied.
Earlier I questioned if the local variable changed, but now let's say that that variable no longer exists at all, why does that even matter if the inner class copied the value and is keeping it for itself? What do you mean? The variable that existed in the method ceased to exist when the method ended. The inner class, however, can continue to live on, and can continue to refer to what we see as the same variable. However, it obviously can't be the same variable, since, in the world of the inner class, it still exists, while in the world of the method, it does not.
This is completely independent of whether the variable changes or not. Regardless or whether the variable changes we still need two copies--one that goes away when the method's stack frame is popped, and one that lives on as long as the inner object does.
Then, because there are two copies, the designers decided that the variable has to be final, so that they wouldn't have to mess with the complexity of keeping two variables in sync.
That explanation leads me to believe that there is no copy and that there is some kind of "permanent umbilical cord" between the inner class and the local variable.Wrong. There has to be a copy. How else could the inner class keep referring to it after the method ends?
Also, does marking it as final force it to be a permanent constant "variable" even if it's not a field "variable"? Or, similarly, does making a "variable" final make Java pretend that it is a field "variable"?Making a variable final does exactly one thing: It means the value can't change after it's been initialized. This is true of both fields and locals.
As for the "pointless" byte-counting, I really don't see how it's confusing unless you're an absolute beginner. If I see somebody using a byte, I assume they have a real reason to do so, not pointless byte-hoarding. Then when I see that it's just a loop counter, I wonder WTF they were thinking, and have to spend some time determining if there's a valid reason, or if they're just writing bad code. Using a byte for a loop counter is bad code.
I could then ask, why are people not using long instead of int and saying that that's using int is too meticulous?Part of it is probably historical. Part of it is because at 4 bytes, and int is exactly on word on the vast majority of hardware that Java has targeted since it came out. 8-byte words are becoming more common (64-bit hardware) but still in the minority.

Is it possible to use a "for loop" structure to represent DAQ of 16 channels?

Hi,
I tried to search but I failed to find a similar problem so I am posting this problem here.
I have a temperature DAQ board which has 16 channels, and I am using all 16 channels to record and monitor temperature data.
When I writed blocks for all 16 channels, a mess was created (as you can see in my attached program). I have noticed that all the VIs for the 16 channels have similar structure, so I was thinking whether we can represent all 16 channels with a "for loop" strucutre with a pointer i scanning from i=1 to 16 as we usually do in Matlab or Fortran.
For instance, we may try to simplify the code like:
for i=1:1:16
acquire data from channel i
show data from channel i in X-Y graph
write data from channel i to excel in every 10 seconds
end
I could not do it myself because I cannot find a "pointer" to represent each channel.
Does anyone know how to do this in LabVIEW? Thank you.
It is said that it is best if we can put all of our code within the screen of a monitor we use by using subVIs to divide the code into many subroutines. But I found it quite difficult to do so as I have too many controls as inputs and indicators as outputs. Also, I use property node to read and write frequently, which make things harder....
Attached code does not work as it requires the 9213 hardware, and for simplicity I deleted irrelavent modules. But if you need I can upload one that may work by modifying the read VI.
Thank you.
Attachments:
ask for help.vi ‏132 KB

Yup, instead of all these 1D arrays, use a single 2D array. Your code could be reduce to <10% of the current size. I am sure it would fit easily on a single screen.
Also try to do some tutorial or take some courses. I realy don't think you are ready to tackle a system of this magnitude at this time.
Your code is just peppered with very poor choices. Some things you apparently haven't figured out:
index array is resizable. There is no need to create dozens of parallel instances, all wired to the same array and all with a unique index diagram constant. If you want all elements in order, the indices don't need to be wired at all.
Replace all your value property nodes with local variables. Much more efficient. Then redesign the code so you don't even need most of the local variables.
You can use built array to append elements to an existing array. Using "insert into array" is much more complicated an error prone.
It is not a good idea to have deeply stacked while loops with the innermost loop having long delays and indeterminate stop conditions. That just gums up the gears.
Learn about proper code architectures, state machines, etc.
Get rid of that gigantic, all encompassing stacked sequence. I am sure you can find a better way to reset three booleans when the code is about to stop. In fact it is typically more reasonable to set things to a defined state when the program starts to avoid problems due to accidental value changes at edit time.
Don't use hidden control/indicators as data storage and interloop communication via local variables. There are better ways.
You can wire the reminder or Q&R directly to a case structure. No need for e.g. "=0".
Don't use ambiguous labels, e.g.a boolean labeled "Dampers on or off". Nobody will be able to later figure out if TRUE corresponds to ON or OFF. Could it be that TRUE mean it is either ON or OFF and FALSE that it is in some imternediate position?
LabVIEW Champion . Do more with less code and in less time .

I have used a 'for loop' to create an array of output data, however I want the each of the data sets from the array to be placed into a 1-D array. How do I concatenate the output of the for loop into a 1-D array?

I am using this to create a data set that will be passed as an anolog output therefore it needs to have the correct array dimensions to go into the analog write vi.

I'm updating my request... I've figured out how to do this by copying an example that uses a simple FOR loop (as seen in the attached current version of my VI). My question now becomes this: Is there a way to save the Y values corresponding to those X values into two more arrays? That is, just for argument's sake, let's say I took the first 100 elements from the X array, and found them to be positive. Then I would like to take the first 100 elements of the Y array and put them into a 'Y Values for X > 0' array. ...And likewise with the negative X values, they should have a separate array of corresponding 'Y values for X < 0' array.
I can see that I should somehow save the indices of the positive X values from the large arrray wh
en I sort them out, and use those indices to pick out the elements from the main Y array with the same indices.
I just can't seem to set up the code necessary to do this. ...Can anyone help, please?
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Poling_Data_Reader_5i.vi ‏79 KB
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How to create parallel tasks using parallel for loops

Hi,
I am setting up a program that communicates with six logic controllers and has to read the system status every 100 ms. We are using OPC datasockets for this, and they appear a little slow.
I have created a uniform comm. method for all controllers, and now I find myself programming this method six times to communicate with each system. I am wondering if this could be done more elegant using the parallel for loop, in which case I would program an exchange once and then have six workers running simultaneously. Since a picture is more clear that a thousand words, what I am asking is this:
Is it possible to replace something like
by
and have this for loop running these tasks in parallel (on different cores / in different threads)?
I have configured the loop to create 8 instances at compile, so I would have 2 instances surplus available at runtime if I find I need an additional system.
The benefits of the method show in the second picture to me are:
* takes less space
* modifications have to be made only once
* less blocks, wires and stuff makes it more clear what's going on.
* flexibility in the actual number of tasks running (8 instances available at runtime)
* if more tasks are required, I need only to update the maximum number of instances and recompile, i.e. no cutting and pasting required.
Unfortunately, I don't have those system available yet, so there's no way to test this. Yet, I would like to know if the above works as I expect - unfortunately the labview help is not completely clear to me on this.
Best regards,
Frans
Solved!
Go to Solution.

Dear mfletcher,
First of all: thanks for confirming that my intuition was right in this case.
As for your question on the help: below is a copy/paste from the help on the 'configure parallelism dialog box'
Number of generated parallel loop instances—Determines the number of For Loop instances LabVIEW generates at compile time. The Number of generated parallel loop instances should equal the number of logical processors on which you expect the VI to execute. If you plan to distribute the VI to multiple computers, Number of generated parallel loop instances should equal the maximum number of logical processors you expect any of those computers to ever contain. Use the parallel instances terminal on the For Loop to specify how many of the generated instances to use at run time. If you wire a larger number to the parallel instances terminal than you specify in this dialog box, LabVIEW only executes as many loop instances as you specify here.The reason for me doubting if what I programmed would work the way I intended lies in the fact that the help only mentions processors here, which would be interpreted as actual cores. Thus on a dual core machine, the number should be 2.
I think it would be helpful to mention something about threads here, because in some case one would like to have more parallel threads than there are cores in a system.
In mu case I would like to create six threads, which on my dual core processor would be spread over only two cores. Then these six threads run in parallel.I know that in case of heavy math that would not help, but since I am doing communications, which have timeouts and such, and that probably runs smoother in six parallel tasks even though I only have two cores.
Hope this helps in improving the help of the for loop.
Regards,
Frans

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

Can a waveform graph be used without for loop

i would like to know if a waveform graph can be used without a for loop and if so, how? I tried using a while loop only, but the reading becomes too fast.
can someone advise

Dear nebb,
first of all, graph is usually an offline plot of the acquired data but to use it as an online display u need to use build arrays in for/while loop which keeps on adding new points & plots in waveform graph.
I am including a vi which incorporates a while loop in which by using build array, points keep on increasing & simultaneously they are plotted in the waveform graph.
Using for or while loop, it has no concern with speed. it depends on the code inside the loop which makes them faster or slower.
For making slow readings, you can put some delay inside while looping.
Hope this works. YOur feedbacks are welcome.
Best Regards,
Nirmal Sharma
India
Attachments:
waveform_graph_without_for_loop.vi ‏17 KB

Create multiple VIs using a for loop

Hi,
I'm still pretty new to LabVIEW, so this question might be easy for you guys here..
I'll simplify what I'm trying to do.
I've got two numeric controllers that act as the rows and columns of a matrix.
I'd like to take those numbers from these two controllers and use them to create a matrix of a certain picture.
Example:
The rows controller is given 3, and the columns controller is given 4.
Using these numbers I would like the end result to show a certain image (let's say, a cube) multiplied on a 3 by 4 matrix.
Let's say the picture is an X, then the end result should be:
XXXX
XXXX
XXXX
I think I should be using a double for loop (one inside the other obviously), and I should also create the "position" property in order to display each picture of the cube in it's right place.
The problem is that I don't know how to CREATE the pictures over and over again, while being able to control each one's position property.
Any help would be GREATLY appreciated!
Solved!
Go to Solution.

1) By "multiple VIs" I meant that I think that I need to create express VIs on the fly while running the for loop. I might be totally wrong here.
2) Yes, by "numeric controllers" I meant numeric controls in the front panel.
3) The matrix I'm referring too isn't an object nor a VI in LabVIEW but a virtual matrix that is the end result. I used the term "matrix" because the end result is actually a matrix (of rows and columns) of pictures..
I'll try to elaborate and even simplify it more:
Let's say I want to display one picture. That's easy, no problem there.
Now let's say that I'd like to display n pictures on a one dimensional array. Just one row.
What I think I need to do is to read from the numeric control in the front panel the number (n) of pictures, and then create them in a for loop, while using the "position" property to set the distance between each picture (using coordinates).
My original question was just like the above, but for a two dimensional matrix/array. So I guess we can even simplify it even more, by saying it's only one dimensional.
My way of action here might be totally wrong, and there might be an easier way or another way to go about this...
Thanks for the quick answer!!

Using a for loop to populate JButton values with letters of Alphabet

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