How do I duplicate the class for each row in a .csv?

Althalus7

I am trying to create a sine wave for every row of data in the .csv but no matter what I try it doesn't seem to work. Do I use arrays? Can someone please tell me or show me how?

Wave wave;
Table neutral;
//A = Amplitude
//C = Horizontal Displacement
//B = Period
void setup() {
  size(500, 500);

  neutral = loadTable("Test.csv", "header");
  println(neutral.getRowCount() + " total rows in table");


  for (TableRow row : neutral.rows ()) {
    //float A = row.getFloat("A");
    //float B = row.getFloat("B");
    //float C = row.getFloat("C");
    //println(A + " : " + B + " : " + C);
    for (int i = 0; i < neutral.getRowCount (); i++) {
      float Ai = neutral.getFloat(i, 4);
      float Bi = neutral.getFloat(i, 5);
      float Ci = neutral.getFloat(i, 6);


      println(Ai + " : " + Bi + " : " + Ci);
      wave = new Wave(0, Ai, Bi/100, 100);
    }
  }
}

void draw() {
  background(255);
  translate(width/2, height/2);
  wave.update();
}

benja

Yes you should use an array if you have more than just a few waves. Define one with a size equal to the number of rows in your table:

Wave[] waveArray = new waveArray[neutral.getRowCount()];

The two nested loops are strange, you don't need to iterate over the rows twice. Just delete the outer loop, then you can access the current row like this:

for (int i=0; i< neutral.getRowCount(); i++) {
  TableRow row = neutral.getRow(i);

  ...
  ...

To get the value of a column you can use row.getFloat() but it only has one parameter (as far as i know). So this would assign the value of the 5th column to the variable Ai:

float Ai = row.getFloat(4);

Then you can create a Wave-Object and store it inside of your array:

  waveArray = new Wave(0, Ai, Bi/100, 100);

I didn't test the code, since i don't have your csv-file, i hope it doesn't have errors.

Althalus7

Thank you :)

benja

Uups.. i'm sorry, made a mistake the last code-snippet should be

waveArray[i] = new Wave(0, Ai, Bi/100, 100);

Althalus7

That's ok but now I seem to be getting a null pointer exception in the 2nd row of the code. Do you know why?

Table neutral;
Wave[] waveCount = new Wave[neutral.getRowCount()];

int width, height;
color fillColor;
float diameter = 6.0;

void setup() {
  // DEFINE THE STAGE
  width = 500;
  height = 550;
  size(500, 550);
  // THE SAME FILL IS USED FOR ALL waveCount
  noFill();
  stroke(0);
  // CREATE A COLLECTION OF waveCount
  neutral = loadTable("Test.csv", "header");
  for (TableRow row : neutral.rows ()) {
    for (int i = 0; i < neutral.getRowCount (); i++) {
      float Ai = neutral.getFloat(i, 4);
      float Bi = neutral.getFloat(i, 5);
      float Ci = neutral.getFloat(i, 6);
      Wave wave = new Wave(0, Ai, Bi/100, 100);
      waveCount[i] = wave;
    }
  }
}

void draw() {
  translate(width/2, height/2);
  background(255);

  for (int i = 0; i < neutral.getRowCount (); i++) {
    waveCount[i].update();
  }
}

benja

That is because "neutral" doesn't exist there. Just declare the array at the top:

Wave[] waveCount;

and after you load the table in line 17 you can initialize it:

waveCount = new Wave[neutral.getRowCount()];

Althalus7

Thank you :)