:: (Foldable t, Monad m) => (a -> m b) -> t a -> m ()

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.

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. As of base 4.8.0.0, mapM_ is just traverse_, specialized to Monad.

Generalized version of mapConcurrently_.

Generalized version of mapConcurrently_.

Map each element of a structure to an Applicative action, evaluate these actions from left to right, and ignore the results. For a version that doesn't ignore the results see traverse. traverse_ is just like mapM_, but generalised to Applicative actions.

Examples

Basic usage:

>>> traverse_ print ["Hello", "world", "!"]
"Hello"
"world"
"!"

Map each element of a structure to an action, evaluate these actions from left to right, and ignore the results. For a version that doesn't ignore the results see traverse.

O(n) Apply the monadic action to all elements of a vector and ignore the results.

O(n) Apply the monadic action to all elements of a vector and ignore the results

Like pooledMapConcurrently but with the return value discarded.

Executes a Traversable container of items concurrently, it uses the Flat type internally. This function ignores the results.

Executes a Traversable container of items concurrently, it uses the Flat type internally. This function ignores the results.

mapConcurrently_ is mapConcurrently with the return value discarded, just like mapM_.

Apply monadic action to each element of vector and ignore result.

forM_ is mapM_ with its arguments flipped. For a version that doesn't ignore the results see forM. forM_ is just like for_, but specialised to monadic actions.

forM_ is mapM_ with its arguments flipped. For a version that doesn't ignore the results see forM. As of base 4.8.0.0, forM_ is just for_, specialized to Monad.

Generalized version of forConcurrently_.

Generalized version of forConcurrently_.

for_ is traverse_ with its arguments flipped. For a version that doesn't ignore the results see for. This is forM_ generalised to Applicative actions. for_ is just like forM_, but generalised to Applicative actions.

Examples

Basic usage:

>>> for_ [1..4] print
1
2
3
4

for_ is traverse_ with its arguments flipped. For a version that doesn't ignore the results see for.

>>> for_ [1..4] print
1
2
3
4