I have a CSV file with a very basic setup. It's a 4 column, 3 row setup. Like this:

A, 1, 2, 3
B, 4, 5, 6
C 7, 8, 9

I want to simply expand it to 6 columns, then write it out as a CSV again. I don't care what the values are at this point for the expanded cells, I'm just curious why everything is coming out as null

1. // the following adds functionality to che-wei wang's CSV import sketch
   // lines.length is the number of rows, wheras csvWidth is the column count
   
   String lines[] = loadStrings("db.csv");
   String [][] csv;
   int csvWidth=0;
   
   //calculate max width of csv file
   for (int i=0; i < lines.length; i++) {
     String [] chars=split(lines[i], ',');
     if (chars.length>csvWidth) {
       csvWidth=chars.length + 2;  // here we expand by 2 columns
     }
   }
   
   //create csv array based on # of rows and columns in csv file
   csv = new String [lines.length][csvWidth];
   
   //parse values into 2d array
   for (int i=0; i < lines.length; i++) {
     String [] temp = new String [lines.length];
     temp= split(lines[i], ',');
     for (int j=0; j < temp.length; j++) {
       csv[i][j]=temp[j];
     }
   }
   
   csv[2][4] = "test";
   
   // now save
   // collapse to a single dimension array
   String[] linesOut = new String[csvWidth * lines.length];
   for (int i = 0; i < lines.length; i++) {
     for (int z = 0; z < csvWidth; z++) {
       linesOut[i] = csv[i][z];
       println(linesOut[i]);
     }
   }
   println(linesOut);
   saveStrings("out.csv", linesOut);
   
   //test
   println(lines.length);

When I println(linesOut) I get [0] null [1] null .. and so on, but if I println(linesOut[0]) I get "A"
Goes without saying that the saved file is also null null null null...