take -bytestring
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.
O(log(min(i,n-i))). The first i elements of a sequence. If i is negative, take i s yields the empty sequence. If the sequence contains fewer than i elements, the whole sequence is returned.
O(n) take n, applied to a Text, returns the prefix of the Text of length n, or the Text itself if n is greater than the length of the Text. Subject to fusion.
O(n) take n, applied to a Text, returns the prefix of the Text of length n, or the Text itself if n is greater than the length of the Text. Subject to fusion.
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] == []
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.
Get the base name, without an extension or path.
> takeBaseName "file/test.txt" == "test"
> takeBaseName "dave.ext" == "dave"
> takeBaseName "" == ""
> takeBaseName "test" == "test"
> takeBaseName (addTrailingPathSeparator x) == ""
> takeBaseName "file/file.tar.gz" == "file.tar"
Get the directory name, move up one level.
> takeDirectory x `isPrefixOf` x || takeDirectory x == "."
> takeDirectory "foo" == "."
> takeDirectory "/foo/bar/baz" == "/foo/bar"
> takeDirectory "/foo/bar/baz/" == "/foo/bar/baz"
> takeDirectory "foo/bar/baz" == "foo/bar"
> Windows: takeDirectory "foo\\bar" == "foo"
> Windows: takeDirectory "foo\\bar\\\\" == "foo\\bar"
> Windows: takeDirectory "C:\\" == "C:\\"
Get the drive from a filepath.
> takeDrive x == fst (splitDrive x)
Get the extension of a file, returns "" for no extension, .ext otherwise.
> takeExtension x == snd (splitExtension x)
> Valid x => takeExtension (addExtension x "ext") == ".ext"
> Valid x => takeExtension (replaceExtension x "ext") == ".ext"
Get all extensions
> takeExtensions "file.tar.gz" == ".tar.gz"
Get the file name.
> takeFileName "test/" == ""
> takeFileName x `isSuffixOf` x
> takeFileName x == snd (splitFileName x)
> Valid x => takeFileName (replaceFileName x "fred") == "fred"
> Valid x => takeFileName (x </> "fred") == "fred"
> Valid x => isRelative (takeFileName x)
Takes the right number of bytes from the input.
O(n) takeWhile, applied to a predicate p and a Text, returns the longest prefix (possibly empty) of elements that satisfy p. Subject to fusion.
O(i) applied to a predicate p and a sequence xs, returns the longest prefix (possibly empty) of xs of elements that satisfy p.
O(i) applied to a predicate p and a sequence xs, returns the longest suffix (possibly empty) of xs of elements that satisfy p.
takeWhileR p xs is equivalent to reverse (takeWhileL p (reverse xs)).
O(1) Return the prefix of the Text of n Word16 units in length.
If n would cause the Text to end inside a surrogate pair, the end of the prefix will be advanced by one additional Word16 unit to maintain its validity.
O(1) Unchecked take of k Word16s from the front of a Text.
The genericTake function is an overloaded version of take, which accepts any Integral value as the number of elements to take.
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