call next on ruby loop from external method

Question

in Ruby it\'s easy to tell loop to go to next item

(1..10).each do |a|
  next if a.even?
  puts a
end

result =>

1
3   
5
         


        

Answer 1

Enumerator#next and Enumerator#peek will be good option to goo :

def my_complex_method(e)
  return if e.peek.even? 
  p e.peek
end
enum = (1..5).each
enum.size.times do |a|
  my_complex_method(enum)
  enum.next
end

Output

1
3
5

Answer 2

If all you need is to take actions on only some of values, based on value returned by my_complex_method you could use enumerators wisely:

(1..10).map { |a| [a, my_complex_method(a)] }.each do |a, success|
  puts a if success
end

You could define method accepting block and take some action in this block based on success or failure there: (1..10).each do |a| my_complex_method { |success| next if success } end Thanks to scoping, you are able not to use `catch`/`throw`, and call `next` based on processing status.

Answer 3

You complex method could return a boolean, and then you compare on your loop like this:

def my_complex_method(item)
  true if item.even? 
end

(1..10).each do |a|
  next if my_complex_method(a)
  puts a
end

A simple approach, but different from the try catch one.

UPDATE

As item.even? already return a boolean value, you don't need the true if item.even? part, you can do as follow:

def my_complex_method(item)
  item.even? 
end