Data.String

The String type and associated operations.

Documentation

type String = [Char]

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

class IsString a where

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

Minimal complete definition

fromString

Methods

fromString :: String -> a

Instances

(~) * a Char => IsString [a]

(a ~ Char) context was introduced in 4.9.0.0

Since: 2.1

Methods

fromString :: String -> [a]

IsString a => IsString (Identity a)

Methods

fromString :: String -> Identity a

IsString a => IsString (Const * a b)

Since: 4.9.0.0

Methods

fromString :: String -> Const * a b

Functions on strings

lines :: String -> [String]

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]

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

unlines :: [String] -> String

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

unwords :: [String] -> String

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