Ruby中并行进程的计数器

Question

我有使用并行gem在不同进程之间分配工作的代码。

Parallel.map(list, :in_processes=>4) do |item|
    if item.name == "A"
        puts "A"
    else
        puts "B"
    end
end

为了获得A和B的确切次数，在进程之间共享计数器的最佳方法是什么？

Answer 1

接收Parallel的返回值（每次迭代的返回值数组），并使用Array＃count方法。

list = ["A","B","A","B","A","B","A","B","A","B"]
result = Parallel.map(list, :in_processes=>4) do |item|
  if item == "A"
    puts "Got A"
    return "A"
  else
    puts "Got B"
    return "B"
  end
end

result # Array of "A" and "B" like ["A","B","A","A","B","B","A","A","B","B"]
# Now, you can do whatever you want with the result array.
count_a = result.count("A") # 5
count_b = result.count("B") # 5

（Ruby不需要显式的return关键字，但我将其放置以避免任何误解。）