base-4.16.0.0: Basic libraries
Copyright(c) The University of Glasgow 2007
LicenseBSD-style (see the file libraries/base/LICENSE)
Maintainerlibraries@haskell.org
Stabilityexperimental
Portabilityportable
Safe HaskellTrustworthy
LanguageHaskell2010

Data.String

Description

The String type and associated operations.

Synopsis

Documentation

type String = [Char] Source #

A String is a list of characters. String constants in Haskell are values of type String.

See Data.List for operations on lists.

class IsString a where Source #

Class for string-like datastructures; used by the overloaded string extension (-XOverloadedStrings in GHC).

Methods

fromString :: String -> a Source #

Instances

Instances details
a ~ Char => IsString [a] #

(a ~ Char) context was introduced in 4.9.0.0

Since: base-2.1

Instance details

Defined in Data.String

Methods

fromString :: String -> [a] Source #

IsString a => IsString (Identity a) #

Since: base-4.9.0.0

Instance details

Defined in Data.String

IsString a => IsString (Const a b) #

Since: base-4.9.0.0

Instance details

Defined in Data.String

Methods

fromString :: String -> Const a b Source #

Functions on strings

lines :: String -> [String] Source #

lines breaks a string up into a list of strings at newline characters. The resulting strings do not contain newlines.

Note that after splitting the string at newline characters, the last part of the string is considered a line even if it doesn't end with a newline. For example,

>>> lines ""
[]
>>> lines "\n"
[""]
>>> lines "one"
["one"]
>>> lines "one\n"
["one"]
>>> lines "one\n\n"
["one",""]
>>> lines "one\ntwo"
["one","two"]
>>> lines "one\ntwo\n"
["one","two"]

Thus lines s contains at least as many elements as newlines in s.

words :: String -> [String] Source #

words breaks a string up into a list of words, which were delimited by white space.

>>> words "Lorem ipsum\ndolor"
["Lorem","ipsum","dolor"]

unlines :: [String] -> String Source #

unlines is an inverse operation to lines. It joins lines, after appending a terminating newline to each.

>>> unlines ["Hello", "World", "!"]
"Hello\nWorld\n!\n"

unwords :: [String] -> String Source #

unwords is an inverse operation to words. It joins words with separating spaces.

>>> unwords ["Lorem", "ipsum", "dolor"]
"Lorem ipsum dolor"