Data.ByteString.Lazy.Char8

O(n) Concatenate a list of ByteStrings.

Map a function over a ByteString and concatenate the results

Applied to a predicate and a ByteString, any determines if any element of the ByteString satisfies the predicate.

Applied to a predicate and a ByteString, all determines if all elements of the ByteString satisfy the predicate.

maximum returns the maximum value from a ByteString

minimum returns the minimum value from a ByteString

O(c) compareLength compares the length of a ByteString to an Int64

scanl is similar to foldl, but returns a list of successive reduced values from the left.

scanl f z [x1, x2, ...] == [z, z `f` x1, (z `f` x1) `f` x2, ...]

Note that

last (scanl f z xs) == foldl f z xs.

scanl1 is a variant of scanl that has no starting value argument.

scanl1 f [x1, x2, ...] == [x1, x1 `f` x2, ...]

scanr is similar to foldr, but returns a list of successive reduced values from the right.

scanr f z [..., x{n-1}, xn] == [..., x{n-1} `f` (xn `f` z), xn `f` z, z]

Note that

head (scanr f z xs) == foldr f z xs
last (scanr f z xs) == z

scanr1 is a variant of scanr that has no starting value argument.

The mapAccumL function behaves like a combination of map and foldl; it applies a function to each element of a ByteString, passing an accumulating parameter from left to right, and returning a final value of this accumulator together with the new ByteString.

The mapAccumR function behaves like a combination of map and foldr; it applies a function to each element of a ByteString, passing an accumulating parameter from right to left, and returning a final value of this accumulator together with the new ByteString.

repeat x is an infinite ByteString, with x the value of every element.

O(n) replicate n x is a ByteString of length n with x the value of every element.

cycle ties a finite ByteString into a circular one, or equivalently, the infinite repetition of the original ByteString.

iterate f x returns an infinite ByteString of repeated applications of f to x:

iterate f x == [x, f x, f (f x), ...]

O(n) The unfoldr function is analogous to the List 'unfoldr'. unfoldr builds a ByteString from a seed value. The function takes the element and returns Nothing if it is done producing the ByteString or returns Just (a,b), in which case, a is a prepending to the ByteString and b is used as the next element in a recursive call.

O(n/c) take n, applied to a ByteString xs, returns the prefix of xs of length n, or xs itself if n > length xs.

O(c) takeEnd n xs is equivalent to drop (length xs - n) xs. Takes n elements from end of bytestring.

>>> takeEnd 3 "abcdefg""efg">>> takeEnd 0 "abcdefg""">>> takeEnd 4 "abc""abc"

O(n/c) drop n xs returns the suffix of xs after the first n elements, or empty if n > length xs.

O(n) dropEnd n xs is equivalent to take (length xs - n) xs. Drops n elements from end of bytestring.

>>> dropEnd 3 "abcdefg""abcd">>> dropEnd 0 "abcdefg""abcdefg">>> dropEnd 4 "abc"""

O(n/c) splitAt n xs is equivalent to (take n xs, drop n xs).

takeWhile, applied to a predicate p and a ByteString xs, returns the longest prefix (possibly empty) of xs of elements that satisfy p.

Returns the longest (possibly empty) suffix of elements satisfying the predicate.

takeWhileEnd p is equivalent to reverse . takeWhile p . reverse.

dropWhile p xs returns the suffix remaining after takeWhile p xs.

Similar to dropWhileEnd, drops the longest (possibly empty) suffix of elements satisfying the predicate and returns the remainder.

dropWhileEnd p is equivalent to reverse . dropWhile p . reverse.

span p xs breaks the ByteString into two segments. It is equivalent to (takeWhile p xs, dropWhile p xs)

spanEnd behaves like span but from the end of the ByteString. We have

spanEnd (not.isSpace) "x y z" == ("x y ","z")

and

spanEnd (not . isSpace) ps
   ==
let (x,y) = span (not.isSpace) (reverse ps) in (reverse y, reverse x)

break p is equivalent to span (not . p).

breakEnd behaves like break but from the end of the ByteString

breakEnd p == spanEnd (not.p)

The group function takes a ByteString and returns a list of ByteStrings such that the concatenation of the result is equal to the argument. Moreover, each string in the result contains only equal elements. For example,

group "Mississippi" = ["M","i","ss","i","ss","i","pp","i"]

It is a special case of groupBy, which allows the programmer to supply their own equality test.

The groupBy function is the non-overloaded version of group.

Returns all initial segments of the given ByteString, shortest first.

O(n) Returns all final segments of the given ByteString, longest first.

Returns all initial segments of the given ByteString, shortest first.

O(n) Returns all final segments of the given ByteString, longest first.

O(n) The stripPrefix function takes two ByteStrings and returns Just the remainder of the second iff the first is its prefix, and otherwise Nothing.

O(n) The stripSuffix function takes two ByteStrings and returns Just the remainder of the second iff the first is its suffix, and otherwise Nothing.

O(n) Break a ByteString into pieces separated by the byte argument, consuming the delimiter. I.e.

split '\n' "a\nb\nd\ne" == ["a","b","d","e"]
split 'a'  "aXaXaXa"    == ["","X","X","X"]
split 'x'  "x"          == ["",""]
split undefined ""      == []  -- and not [""]

and

intercalate [c] . split c == id
split == splitWith . (==)

As for all splitting functions in this library, this function does not copy the substrings, it just constructs new ByteStrings that are slices of the original.

O(n) Splits a ByteString into components delimited by separators, where the predicate returns True for a separator element. The resulting components do not contain the separators. Two adjacent separators result in an empty component in the output. eg.

splitWith (=='a') "aabbaca" == ["","","bb","c",""]
splitWith undefined ""      == []  -- and not [""]

lines lazily splits a ByteString into a list of ByteStrings at newline Chars ('\n'). The resulting strings do not contain newlines. The first chunk of the result is only strict in the first chunk of the input.

Note that it does not regard CR ('\r') as a newline character.

words breaks a ByteString up into a list of words, which were delimited by Chars representing white space. And

tokens isSpace = words

unlines joins lines, appending a terminating newline after each.

Equivalent to concat . Data.List.concatMap (\x -> [x, singleton '\n']).

The unwords function is analogous to the unlines function, on words.

O(n) elem is the ByteString membership predicate. This implementation uses memchr(3).

O(n) notElem is the inverse of elem

O(n) The find function takes a predicate and a ByteString, and returns the first element in matching the predicate, or Nothing if there is no such element.

O(n) filter, applied to a predicate and a ByteString, returns a ByteString containing those characters that satisfy the predicate.

O(n) Make a copy of the ByteString with its own storage. This is mainly useful to allow the rest of the data pointed to by the ByteString to be garbage collected, for example if a large string has been read in, and only a small part of it is needed in the rest of the program.

getContents. Equivalent to hGetContents stdin. Will read lazily

Write a ByteString to stdout.

The chunks will be written one at a time. Other threads might write to the stdout in between, and hence putStr alone is not suitable for concurrent writes.

Write a ByteString to stdout, appending a newline byte.

The chunks will be written one at a time, followed by a newline. Other threads might write to the stdout in between, and hence putStrLn alone is not suitable for concurrent writes.

The interact function takes a function of type ByteString -> ByteString as its argument. The entire input from the standard input device is passed to this function as its argument, and the resulting string is output on the standard output device.

Read an entire file lazily into a ByteString.

The Handle will be held open until EOF is encountered.

Note that this function's implementation relies on hGetContents. The reader is advised to read its documentation.

Write a ByteString to a file.

Append a ByteString to a file.

Read entire handle contents lazily into a ByteString. Chunks are read on demand, using the default chunk size.

File handles are closed on EOF if all the file is read, or through garbage collection otherwise.

Read n bytes into a ByteString, directly from the specified Handle.

hGetNonBlocking is similar to hGet, except that it will never block waiting for data to become available, instead it returns only whatever data is available. If there is no data available to be read, hGetNonBlocking returns empty.

Note: on Windows and with Haskell implementation other than GHC, this function does not work correctly; it behaves identically to hGet.

Outputs a ByteString to the specified Handle.

The chunks will be written one at a time. Other threads might write to the Handle in between, and hence hPut alone is not suitable for concurrent writes.

Similar to hPut except that it will never block. Instead it returns any tail that did not get written. This tail may be empty in the case that the whole string was written, or the whole original string if nothing was written. Partial writes are also possible.

Note: on Windows and with Haskell implementation other than GHC, this function does not work correctly; it behaves identically to hPut.

A synonym for hPut, for compatibility

Write a ByteString to a handle, appending a newline byte.

The chunks will be written one at a time, followed by a newline. Other threads might write to the Handle in between, and hence hPutStrLn alone is not suitable for concurrent writes.