Question

I have N values (integer). I’d like to know what is the most elegant way to randomly pick one of those values regarding a percentage. For example, for a 3 values example:

• Value 1 has 30% chance to get picked
• Value 2 has 12% chance to get picked
• Value 3 has 45% chance to get picked

I need this for a program i’m developing with Java but a pseudo code algorithm or a code in any other language would be ok.

Answer 1

One way of doing this without calculating values to use is

double d = Math.random() * 100;
if ((d -= 30) < 0) return 1;
if ((d -= 12) < 0) return 2;
if ((d -= 45) < 0) return 3;
return 4;