(rand-weighted ..args) args: two or more arguments (any type) returns any type

F

Randomly selects one item from a group, with unequal probability.

Expects an even number of arguments, where the even-numbered arguments are all non-negative numbers (weights). The sum of all weights must be greater than 0.

Each argument's likelihood of being chosen is equal to `(/ weight sum)`

. For example,
`(rand-weighted 'x 2 'y 3 'z 0)`

has a two-in-five chance of returning `'x`

and a
three-in-five chance of returning `'y`

. It will never return `'z`

.