问题
I just asked a question about return and it seems to do the same thing as break. How do you use return, and how do you use break, such as in the actual code that you write to solve the problems that can use these constructs.
I can't really post examples because I don't know how to use these so they wouldn't make much sense.
回答1:
Return exits from the entire function.
Break exits from the innermost loop.
Thus, in a function like so:
def testing(target, method)
(0..100).each do |x|
(0..100).each do |y|
puts x*y
if x*y == target
break if method == "break"
return if method == "return"
end
end
end
end
To see the difference, try:
testing(50, "break")
testing(50, "return")
回答2:
break is called from inside a loop. It will put you right after the innermost loop you are in.
return is called from within methods. It will return the value you tell it to and put you right after where it was called.
回答3:
I wanted to edit the approved answer to simplify the example, but my edit was rejected with suggestion of making new answer. So this is my simplified version:
def testing(target, method)
(1..3).each do |x|
(1..3).each do |y|
print x*y
if x*y == target
break if method == "break"
return if method == "return"
end
end
end
end
we can see the difference trying:
testing(3, "break")
testing(3, "return")
Results of first (break statement exiting innermost loop only when 3 reached):
1232463
Results of last (return statement exiting whole function):
123
回答4:
One more example could be if you have two loops in a single method and if you want to come out of the first loop and continue to the second loop use break in the first loop or vice versa:
def testing(method)
x=1
10.times do
if(x == 2)
break if method == "break"
end
x+=1
end
10.times do
if(x == 5)
return if method == "return"
end
x+=1
end
end
来源：https://stackoverflow.com/questions/4601631/break-and-return-in-ruby-how-do-you-use-them