How to sort a ruby array in ascending order but keep zero last

Question

I am trying to sort a Ruby array with the following function

@prices = @item.prices.sort { |x,y| x.total <=> y.total }

Which orders from the lowest to the highest cost. However some products have a total of 0.00 and I want them to appear last rather than at the top.

I have tried a few things but would like some way to modify this block to sort zero at the bottom but keep the rest in ascending order.

Thanks.

Answer 1

Try this out, I think it is doing what you request:

@prices = @item.prices.sort {|a,b| a.total==0 ? 1 : b.total==0 ? -1 : a.total<=>b.total}

Answer 2

Just for the record:

>> a = [0, 1, 3, 0, 2, 5, 0, 9]
=> [0, 1, 3, 0, 2, 5, 0, 9]
>> a.sort_by { |x| x.zero? ? Float::MAX : x }
=> [1, 2, 3, 5, 9, 0, 0, 0]

On most platforms 1.0/0 will evaluate to Infinity, so you can also use this instead of Float::MAX:

>> b = [1,4,2,0,5,0]
=> [1, 4, 2, 0, 5, 0]
>> Inf = 1.0/0
=> Infinity
>> b.sort_by { |x| x.zero? ? Inf : x }
=> [1, 2, 4, 5, 0, 0]