replicate -package:Cabal -package:base -package:bytestring -package:memory -package:dlist -package:vector package:streamly

>>> replicate n = Stream.take n . Stream.repeat

Generate a stream of length n by repeating a value n times.

>>> replicateM n = Stream.take n . Stream.repeatM

Generate a stream by performing a monadic action n times. Same as:

>>> pr n = threadDelay 1000000 >> print n

This runs serially and takes 3 seconds:

>>> Stream.drain $ Stream.fromSerial $ Stream.replicateM 3 $ pr 1
1
1
1

This runs concurrently and takes just 1 second:

>>> Stream.drain $ Stream.fromAsync  $ Stream.replicateM 3 $ pr 1
1
1
1

Concurrent

Generate a stream by concurrently performing a monadic action n times. Definition:

>>> parReplicateM cfg n = Stream.parSequence cfg . Stream.replicate n

Example, parReplicateM in the following example executes all the replicated actions concurrently, thus taking only 1 second:

>>> Stream.fold Fold.drain $ Stream.parReplicateM id 10 $ delay 1
...