Choose a random entry from an array/arrayList?

Programming Questions

yanom0

Choose a random entry from an array/arrayList?

in Programming Questions • 2 years ago

This seems like a simple thing, but it's been eluding me all day. How do I choose a random entry in an array or ArrayList? All of my solutions either end up producing values out of range or some elements in the ArrayList don't ever get picked (the first or last ones, sometimes). Does anyone know how?

Replies(3)

veeableful

Re: Choose a random entry from an array/arrayList?

2 years ago

Here's a simple way using Processing's random() function:

ArrayList<Integer> num = new ArrayList<Integer>();
for (int i = 0; i < 6; i++) {
num.add(i);
}
int randomIdx = (int) random(num.size()); // you have to cast it into integer because random() returns a float
println(num.get(randomIdx));