Question

I was doing some operations with arrays, like this (very simple)

a = [1, 2, 3, 4]
b = [1]
b.push((a-b).sample)
=> [1, 2]

Ok, let’s see some times its value

b
=> [1, 2]
b
=> [1, 3]
b
=> [1, 2]
b
=> [1, 4]    

I don’t understand why b changes. I supposed that i took a random element from de difference between a and b, and append it to b, so… where am i wrong?

EDIT:

Today is a new day, and magically, the same code runs ok…. it’s a mistery
Thank’s all!

Answer 1

Is this what you expect to get?

a = [1,2,3,4]
b = []
0.upto(3) do
    b.push((a-b).sample)
    puts b
end

  #=>  [2]
  #=>  [2, 4]
  #=>  [2, 4, 1]
  #=>  [2, 4, 1, 3]