Question

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How do I pick randomly from an array?

What is the appropriate way to ensure that a non-existent item isn’t chosen?

 icons = %w[asterisk star arrow]
 random = rand(icons.length)

or

icons = %w[asterisk star arrow]
random = rand(icons.length -1)

Answer 1

How about using Array#sample

[1, 2, 3].sample(1)

sample → obj
sample(random: rng) → obj
sample(n) → new_ary
sample(n, random: rng) → new_ary
Choose a random element or n random elements from the array. The elements are chosen by using random and unique indices into the array in order to ensure that an element doesn’t repeat itself unless the array already contained duplicate elements. If the array is empty the first form returns nil and the second form returns an empty array.
If rng is given, it will be used as the random number generator.

(Assuming you are more interested on the element rather than the index)