Equivalent of “continue” in Ruby

问题:

In C and many other languages, there is a continue keyword that, when used inside of a loop, jumps to the next iteration of the loop. Is there any equivalent of this continue keyword in Ruby?

回答1:

Yes, it's called next.

for i in 0..5
   if i < 2
     next
   end
   puts "Value of local variable is #{i}"
end

This outputs the following:

Value of local variable is 2
Value of local variable is 3
Value of local variable is 4
Value of local variable is 5
 => 0..5 

回答2:

next

also, look at redo which redoes the current iteration.

回答3:

Writing Ian Purton's answer in a slightly more idiomatic way:

(1..5).each do |x|
  next if x < 2
  puts x
end

Prints:

  2
  3
  4
  5

回答4:

Inside for-loops and iterator methods like each and map the next keyword in ruby will have the effect of jumping to the next iteration of the loop (same as continue in C).

However what it actually does is just to return from the current block. So you can use it with any method that takes a block - even if it has nothing to do with iteration.

回答5:

Ruby has two other loop/iteration control keywords: redo and retry. Read more about them, and the difference between them, at Ruby QuickTips.

回答6:

I think it is called next.