ruby

How to iterate over all but first element of an enumerable

I run the following code:

> a = [1,2,3].collect
 => #<Enumerator: [1, 2, 3]:collect> 
> b = a.next
 => 1 
> a.each do |x| puts x end
1
2
3
=> [nil, nil, nil]

I would expect the result of the do to be 2, 3 since I've already read the first element of a. How I achieve a result of 2, 3 elegantly?

Edit:

To clarify, I don't want to skip the first entry, I just want to process it differently. So I want both b and the loop.

Solution

  • How about this?

    [1,2,3].drop(1).each {|x| puts x }
# >> 2
# >> 3

    Here's how you can continue walking the iterator

    a = [1,2,3]

b = a.each # => #<Enumerator: [1, 2, 3]:each>
b.next # skip first one

loop do
  c = b.next
  puts c
end
# >> 2
# >> 3