问题
How do you tell a Ruby program to wait an arbitrary amount of time before moving on to the next line of code?
回答1:
Like this:
sleep(num_secs)
The num_secs value can be an integer or float.
Also, if you're writing this within a Rails app, or have included the ActiveSupport library in your project, you can construct longer intervals using the following convenience syntax:
sleep(4.minutes)
# or, even longer...
sleep(2.hours); sleep(3.days) # etc., etc.
# or shorter
sleep(0.5) # half a second
回答2:
Use sleep like so:
sleep 2
That'll sleep for 2 seconds.
Be careful to give an argument. If you just run sleep, the process will sleep forever. (This is useful when you want a thread to sleep until it's woken.)
回答3:
I find until very useful with sleep. example:
> time = Time.now
> sleep 2.seconds until Time.now > time + 10.seconds # breaks when true
回答4:
sleep 6 will sleep for 6 seconds. For a longer duration, you can also use sleep(6.minutes) or sleep(6.hours).
来源：https://stackoverflow.com/questions/1329967/tell-ruby-program-to-wait-some-amount-of-time