Variable variables in java? Am i misunderstanding array usage?

Question

I've a list of ~50 describable objects. Each has its own array of possible descriptors. I'm trying to write code that iterates through the list, selects a random descriptor from the matching array, and stores into a final array for output.

"list[i][]" represents a variable variable, _not_ a multidimensional array. Obvs doesn't work.

Random r = new Random();
for (i<list.length){
int x = r.nextInt(list[i][].length);
output[i] = list[i][x];
}

Also, would a proper 2d array work here? And how?

Answer 1

You make a wrong declaration of your multidimensional array.

u must move between your list[i][j], not only list[i][];

an example:

public void set(int i){
for (int j=0;j<list[0].length;j++){
list[i][j]=(int)(Math.random()*10+1);
}

/* list[0] is used for column of your multidimensional array as a matrix */

in your case:
int x = r.nextInt(list.length);

Answer 2

ok, now your for cycles are not good.

for costruction is made by:
(INITIALIZE_VARIABLE; CONDITION; INCREASE/DECREASE_VARIABLE)

then this "databank[i][j].length" are wrong, doesnt exist, or .length or [0].length, or line or column.
Do u want the number of all elements (line*column) or what?

for(int i=0;i<databank.length;i++){
for(int j=0;j<databank[0].length;j++){
int x=r.nextInt(databank.length*databank[0].length);

this line
output[i] = databank[i][x];
for what? random numbers in the output array?

Answer 3

I've posted a working 2d array program sort of solving this on my profile. Code critiques are welcomed there.