ruby - Assign array elements randomly but ensure that all are used?

Question

How can the assignment of array elements into different objects be randomised such that

• there's no recycling of array elements (i.e. the same array element is never used more than once, unless it was a duplicate), and
• all values get used, including duplicates. The resulting number of objects created should be the same as the length of the array
• it works for array elements that aren't necessarily single integers

Example

An array [1, 2] would have two possible outcomes:

1. a = 1 and b = 2, OR
2. a = 2 and b = 1.

An array of [1, 2, 3] would have 6 possible outcomes.

Use case

I want to randomly sample inputs to a rails mailer preview, but the inputs aren't all of the same class, so I can't do something like Customer.all.sample

I also can't simply combine the possible inputs into an array and sample from it, since that could cause the same element to get used more than once.

question from:https://stackoverflow.com/questions/65877376/assign-array-elements-randomly-but-ensure-that-all-are-used

Answer 1

.sample will sample without replacement by default.

So, for example,

arr = [1, 2, 3]

a, b, c = arr.sample(arr.length)

a
=> 3

b
=> 1

c
=> 2