rubyiterationmetaprogrammingproc

Skipping iteration from Proc

I'm wondering if it's possible to use a Proc for skipping iteration in Ruby?

I wrote some piece of code

def validation i
  pr = Proc.new do |i|
    if i < 3
      next
    end
  end
  pr.call(i)
end

(1..5).each do |i|
  validation i
  puts "#{i} is bigger than 3"
end

and I expected something like this as result:

3 is bigger than 3
4 is bigger than 3
5 is bigger than 3

but instead I got:

1 is bigger than 3
2 is bigger than 3
3 is bigger than 3
4 is bigger than 3
5 is bigger than 3

So is it possible to use somehow next in Proc for skipping from outer iteration or there is some other way?

Solution

  • You can't call next in your validation method because the loop is external. What you can do is use next within your (1..5).each loop that's dependent on a call to validation. The following code produces your desired result.

    Edit - The code has been refactored to make appropriate use of Proc.

    pr = Proc.new {|i| i < 3}

(1..5).each do |i|
  next if pr.call(i)
  puts "#{i} is bigger than 3"
end