array#rand syntax question

Hey Lawrence,

No worries! I understand what you're asking now.

The ruby rand command is going to pick a random number using the length of the array that is passed in through the methods parameters.

Lets say I make a random array of numbers:

array_example = [1, 2, 3, 4, 5, 6, 7, 8]

And I use the array I just made and plugged it into your code from above:

random_select(array_example, 2)

Then the following should happen and other people should please correct me if I'm wrong. The rand command will take the length of my array_example and pick a random number from it.

From this:

def random_select([1, 2, 3, 4, 5, 6, 7, 8], 2)
  new_array = []
  2.times do 
    new_array << [1, 2, 3, 4, 5, 6, 7, 8][rand([1, 2, 3, 4, 5, 6, 7, 8].length)]
  end 

  return new_array 
end

To this:

def random_select([1, 2, 3, 4, 5, 6, 7, 8], 2)
  new_array = []
  2.times do 
    new_array << [1, 2, 3, 4, 5, 6, 7, 8][rand(8)]
  end 

  return new_array 
end

So now it'll just pick a random number from 0 to 7 and pick the number in that index. If rand(8) come out as 7, the number in the 7th index would be picked which is the number 8.

I hope that makes sense to you. Let me know if any part of this needs more clarifying.

Thanks!

Hey Lawrence,

Check out this link for a good explanation: https://www.ruby-forum.com/topic/4403714

It looks like there is no array.rand but there is an array.sample method that will, "Choose a random element or n random elements from the array." Check out: http://www.ruby-doc.org/core-2.0/Array.html#method-i-sample

But the code above looks pretty snazzy.

Although, you could build your own rand method for the Array class if you'd so choose to do. :)

I hope that helps.

Hey Neil,

thanks for the comment! I apologize I should have clarified what I was asking. My question is what does the brackets in the code below do?

array[rand(array.length)]

I have never seen that syntax and could not find an answer so wanted to ask the treehouse community. thanks!