# mapM_

Map each element of a structure to a monadic action, evaluate these actions from left to right, and ignore the results. For a version that doesn't ignore the results see mapM. mapM_ is just like traverse_, but specialised to monadic actions.
O(n) Apply the monadic action to all elements of a vector and ignore the results.
Apply a monadic action to each element of the stream
Execute a monadic action for each element of the Bundle
O(n) Apply the monadic action to all elements of a vector and ignore the results.
O(n) Apply the monadic action to every element of the vector, discarding the results.
O(n) Apply the monadic action to every element of the vector, discarding the results.
O(n) Apply the monadic action to all elements of a vector and ignore the results.
O(n) Apply the monadic action to every element of the vector, discarding the results.
O(n) Apply the monadic action to all elements of a vector and ignore the results.
O(n) Apply the monadic action to every element of the vector, discarding the results.
O(n) Apply the monadic action to all elements of a vector and ignore the results.
O(n) Apply the monadic action to every element of the vector, discarding the results.
Apply the action to all values in the stream. Note: if you want to pass the values instead of consuming them, use iterM instead. Subject to fusion
Apply the action to all values in the stream. Subject to fusion Since 0.3.0
Perform a computation on each Word8 in a stream. Since 1.0.10
Consume all values using a monadic function
Converts an effectful function to a fold. Specialized version of sink.
Maps a side effect over an InputStream. mapM_ f s produces a new input stream that passes all output from s through the side-effecting IO action f. Example:
```ghci> Streams.fromList [1,2,3] >>=
Streams.mapM_ (putStrLn . show . (*2)) >>=
Streams.toList
2
4
6
[1,2,3]
```
A side-effecting map over the key-value records of a hash table. O(n).
See the documentation for this function in mapM_.
See the documentation for this function in mapM_.
See the documentation for this function in mapM_.
See the documentation for this function in Data.HashTable.Class#v:mapM_.
Reduce a stream to its return value with a monadic action.
```>>> S.mapM_ Prelude.print \$ each [1..3]
1
2
3
```
```>>> rest <- S.mapM_ Prelude.print \$ S.splitAt 3 \$ each [1..10]
1
2
3

>>> S.sum rest
49 :> ()
```