Shortening enumeration code

Question

What is a succinct way of accomplishing this in Ruby? I simply want to wait until all objects are running. This seems too wordy.

# arr contains objects that respond to running?
all_running = false
until all_running
    sleep 0.5
    all_running = true
    arr.each{ |obj|
        all_running = all_running and obj.running?
    }

end

score 6 · Accepted Answer · answered Sep 08 '11 at 08:21

6

sleep 0.5 until arr.all? &:running?

answered Sep 08 '11 at 08:21

Simon Ernst

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9
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ah, found this http://stackoverflow.com/questions/1961030/ruby-ruby-on-rails-ampersand-colon-shortcut – Morrowless Sep 08 '11 at 08:29
1

It's a shorter way to write `arr.all? {|obj| obj.running?}`. – Benoit Garret Sep 08 '11 at 08:29
1

It's a `Symbol#to_proc` shorthand, equivalent to `{|i| i.running?}`. This may be Rails specific, just try it in irb :) – Simon Ernst Sep 08 '11 at 08:29

score 0 · Answer 2 · answered Sep 08 '11 at 08:19

0

How about

sleep(0.5) until arr.inject(true) { |all_running, obj| all_running and obj.running? }

answered Sep 08 '11 at 08:19

eugen

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65

You should replace your code in the context, it only replaces the inner loop but you give the impression that it replaces the whole code. – Benoit Garret Sep 08 '11 at 08:20

Shortening enumeration code

2 Answers2