getting a value from a previous loop to use in the current loop

Question

How do I use a value from the previous iteration in my current loop? I am generating a double [] v and want to do v - w where w is the value of v in the previous iteration. Obviously I need to implement subtraction for 2 arrays.

if (!e.getValueIsAdjusting()) 
                {
                    double[] v = new double[uaCount.get(table.getValueAt(table.getSelectedRow(),0)).singleValues.size()];
                    int i = 0;
                    for(Long j : uaCount.get(table.getValueAt(table.getSelectedRow(),0)).singleValues) 
                    {
                      v[i++] = j.doubleValue();
                    }
                    double [] w, r;
                    //implement r = v-w
                    System.out.println(String.valueOf(uaCount.get(table.getValueAt(table.getSelectedRow(),0)).singleValues));
                    dataset.addSeries("Histogram",r, 1000, 0, 120000);  
                }

the purpose of this is to add a new dataset to my histogram while getting rid of the previous one. Now that I think about this more though, subtracting the values will give me different answers right?

You've asked a [series of duplicate questions](http://stackoverflow.com/users/2007843/user2007843) on this topic going back to this [question](http://stackoverflow.com/q/16085734/230513). I've cited several complete examples. As suggested [here](http://stackoverflow.com/a/16176221/230513), you can "Replace the entire dataset in the plot." Please edit your question to include an [sscce](http://sscce.org/) that shows your current approach. Use a _small_ `TableModel` having a _few_ rows and columns. — trashgod, Apr 24 '13 at 23:38

score 3 · Accepted Answer · answered Apr 24 '13 at 20:18

3

How do I use a value from the previous iteration in my current loop?

Just save the loop's current value as previous as the last line in the end of the loop.
In your first line of the loop when you re-enter, previous has the previous value

answered Apr 24 '13 at 20:18

Cratylus

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score 1 · Answer 2 · answered Apr 24 '13 at 20:18

1

declare a variable outside your loop to hold it

int val;
int prev;

for(int i=0; i<n; i++)
{
    //do stuff with val
    ...
    prev = val;
}

answered Apr 24 '13 at 20:18

Sam I am says Reinstate Monica

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score 0 · Answer 3 · answered Apr 24 '13 at 20:49

Assuming from your explanation your reuirment is to do something like:

for(initialization;condition;increment){
curr[i] = i;//holds your current ittration value
if(prev != null){
//do some operation
//these extra things can also be done by cure[i-1] instead of using extra variable just    //check if i>0 then get the previous value from your curr array and perform operation //accordingly
}
prev = curr[i];
}

Approach 2: As suggested by other users you can make use of collection framework which will be more simpler.

getting a value from a previous loop to use in the current loop

3 Answers3