06 - writing block methods that classify or collect.rb

来自「O Reilly Ruby Cookbook source code」· RB 代码 · 共 15 行

module Enumerable
  def find_no_more_than(limit)
    inject([]) do |a,e|
      a << e if yield e
      return a if a.size >= limit
      a
    end    
  end
end

#---
a = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
a.find_no_more_than(3) { |x| x % 2 == 0 }            # => [2, 4, 6]
#---