take -containers +base

take :: Int -> [a] -> [a]
base Prelude, base Data.List
take n, applied to a list xs, returns the prefix of xs of length n, or xs itself if n > length xs: > take 5 "Hello World!" == "Hello" > take 3 [1,2,3,4,5] == [1,2,3] > take 3 [1,2] == [1,2] > take 3 [] == [] > take (-1) [1,2] == [] > take 0 [1,2] == [] It is an instance of the more general Data.List.genericTake, in which n may be of any integral type.
takeWhile :: (a -> Bool) -> [a] -> [a]
base Prelude, base Data.List
takeWhile, applied to a predicate p and a list xs, returns the longest prefix (possibly empty) of xs of elements that satisfy p: > takeWhile (< 3) [1,2,3,4,1,2,3,4] == [1,2] > takeWhile (< 9) [1,2,3] == [1,2,3] > takeWhile (< 0) [1,2,3] == []
takeMVar :: MVar a -> IO a
base Control.Concurrent.MVar
Return the contents of the MVar. If the MVar is currently empty, takeMVar will wait until it is full. After a takeMVar, the MVar is left empty. There are two further important properties of takeMVar: * takeMVar is single-wakeup. That is, if there are multiple threads blocked in takeMVar, and the MVar becomes full, only one thread will be woken up. The runtime guarantees that the woken thread completes its takeMVar operation. * When multiple threads are blocked on an MVar, they are woken up in FIFO order. This is useful for providing fairness properties of abstractions built using MVars.
genericTake :: Integral i => i -> [a] -> [a]
base Data.List
The genericTake function is an overloaded version of take, which accepts any Integral value as the number of elements to take.
tryTakeMVar :: MVar a -> IO (Maybe a)
base Control.Concurrent.MVar
A non-blocking version of takeMVar. The tryTakeMVar function returns immediately, with Nothing if the MVar was empty, or Just a if the MVar was full with contents a. After tryTakeMVar, the MVar is left empty.