[英]How can I run a list of independent IO actions in parallel?
Is there something that does the same thing as sequenceA
does to [IO a]
, but that runs them concurrently?是否有与
sequenceA
对[IO a]
做同样的事情,但同时运行它们的东西? I don't need any fancy concurrency stuff like locking since all IO actions are independent.我不需要任何花哨的并发东西,比如锁定,因为所有 IO 操作都是独立的。
The async
package works well for this. async
package 对此非常有效。 As mentioned in a comment, mapConcurrently
from that package will run a list of IO actions in parallel.如评论中所述,
mapConcurrently
从 package 将并行运行 IO 操作列表。 In particular, specialized to a list, the expression mapConcurrently id
has the type you want:特别是,专门用于列表,表达式
mapConcurrently id
具有您想要的类型:
mapConcurrently id :: [IO a] -> IO [a]
so:所以:
import Control.Concurrent.Async
main = mapConcurrently id [putStrLn "foo", putStrLn "bar"]
If you don't care about the return values, use mapConcurrently_ id
instead.如果您不关心返回值,请改用
mapConcurrently_ id
。
If you don't actually need IO and are really tring to run a bunch of pure computations in parallel, then the parallel
package would be more appropriate.如果您实际上并不需要 IO 并且真的想并行运行一堆纯计算,那么
parallel
package 会更合适。
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