Generating random numbers

This lesson covers generating random numbers with Julia's rand, with the aim of building things with a random element such as dice or rock-paper-scissors.

rand() picks values at random from a range or a collection. Use it for dice, lotteries, and the like — the result changes on every run.

The sample code picks a dice roll from 1 to 6 with rand(1:6) and one of Rock, Scissors, or Paper from an array with rand(choices). Note the consistency of the same rand() serving both a range and a collection.

A common early stumble is how many things rand() accepts. Its behaviour changes with what you pass — a range, an array, a type — so it is worth confirming you are using it as intended.

In professional work, this is indispensable wherever you want an unpredictable element — shuffling in a game, sampling in a simulation.