base-4.9.1.0: Basic libraries

Copyright | (c) The University of Glasgow 2007
License | BSD-style (see the file libraries/base/LICENSE)
Maintainer | libraries@haskell.org
Stability | experimental
Portability | portable
Safe Haskell | Trustworthy
Language | Haskell2010

Data.String

Contents

- Functions on strings

Description

The `String` type and associated operations.

Synopsis

- type String = [Char]
- class IsString a where
- lines :: String -> [String]
- words :: String -> [String]
- unlines :: [String] -> String
- unwords :: [String] -> String

# Documentation

type String = [Char] Source #

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

class IsString a where Source #

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

Minimal complete definition

fromString

Methods

fromString :: String -> a Source #

Instances

(~) * a Char => IsString [a] # |
Methods fromString :: String -> [a] Source #
IsString a => IsString (Identity a) # |
Methods fromString :: String -> Identity a Source #
IsString a => IsString (Const * a b) # |
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.

unlines :: [String] -> String Source #

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

unwords :: [String] -> String Source #

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