2 :mod:`textwrap` --- Text wrapping and filling
3 =============================================
6 :synopsis: Text wrapping and filling
7 .. moduleauthor:: Greg Ward <gward@python.net>
8 .. sectionauthor:: Greg Ward <gward@python.net>
13 The :mod:`textwrap` module provides two convenience functions, :func:`wrap` and
14 :func:`fill`, as well as :class:`TextWrapper`, the class that does all the work,
15 and a utility function :func:`dedent`. If you're just wrapping or filling one
16 or two text strings, the convenience functions should be good enough;
17 otherwise, you should use an instance of :class:`TextWrapper` for efficiency.
20 .. function:: wrap(text[, width[, ...]])
22 Wraps the single paragraph in *text* (a string) so every line is at most *width*
23 characters long. Returns a list of output lines, without final newlines.
25 Optional keyword arguments correspond to the instance attributes of
26 :class:`TextWrapper`, documented below. *width* defaults to ``70``.
29 .. function:: fill(text[, width[, ...]])
31 Wraps the single paragraph in *text*, and returns a single string containing the
32 wrapped paragraph. :func:`fill` is shorthand for ::
34 "\n".join(wrap(text, ...))
36 In particular, :func:`fill` accepts exactly the same keyword arguments as
39 Both :func:`wrap` and :func:`fill` work by creating a :class:`TextWrapper`
40 instance and calling a single method on it. That instance is not reused, so for
41 applications that wrap/fill many text strings, it will be more efficient for you
42 to create your own :class:`TextWrapper` object.
44 Text is preferably wrapped on whitespaces and right after the hyphens in
45 hyphenated words; only then will long words be broken if necessary, unless
46 :attr:`TextWrapper.break_long_words` is set to false.
48 An additional utility function, :func:`dedent`, is provided to remove
49 indentation from strings that have unwanted whitespace to the left of the text.
52 .. function:: dedent(text)
54 Remove any common leading whitespace from every line in *text*.
56 This can be used to make triple-quoted strings line up with the left edge of the
57 display, while still presenting them in the source code in indented form.
59 Note that tabs and spaces are both treated as whitespace, but they are not
60 equal: the lines ``" hello"`` and ``"\thello"`` are considered to have no
61 common leading whitespace. (This behaviour is new in Python 2.5; older versions
62 of this module incorrectly expanded tabs before searching for common leading
68 # end first line with \ to avoid the empty line!
73 print repr(s) # prints ' hello\n world\n '
74 print repr(dedent(s)) # prints 'hello\n world\n'
77 .. class:: TextWrapper(...)
79 The :class:`TextWrapper` constructor accepts a number of optional keyword
80 arguments. Each argument corresponds to one instance attribute, so for example
83 wrapper = TextWrapper(initial_indent="* ")
87 wrapper = TextWrapper()
88 wrapper.initial_indent = "* "
90 You can re-use the same :class:`TextWrapper` object many times, and you can
91 change any of its options through direct assignment to instance attributes
94 The :class:`TextWrapper` instance attributes (and keyword arguments to the
95 constructor) are as follows:
100 (default: ``70``) The maximum length of wrapped lines. As long as there
101 are no individual words in the input text longer than :attr:`width`,
102 :class:`TextWrapper` guarantees that no output line will be longer than
103 :attr:`width` characters.
106 .. attribute:: expand_tabs
108 (default: ``True``) If true, then all tab characters in *text* will be
109 expanded to spaces using the :meth:`expandtabs` method of *text*.
112 .. attribute:: replace_whitespace
114 (default: ``True``) If true, each whitespace character (as defined by
115 ``string.whitespace``) remaining after tab expansion will be replaced by a
120 If :attr:`expand_tabs` is false and :attr:`replace_whitespace` is true,
121 each tab character will be replaced by a single space, which is *not*
122 the same as tab expansion.
125 .. attribute:: drop_whitespace
127 (default: ``True``) If true, whitespace that, after wrapping, happens to
128 end up at the beginning or end of a line is dropped (leading whitespace in
129 the first line is always preserved, though).
131 .. versionadded:: 2.6
132 Whitespace was always dropped in earlier versions.
135 .. attribute:: initial_indent
137 (default: ``''``) String that will be prepended to the first line of
138 wrapped output. Counts towards the length of the first line.
141 .. attribute:: subsequent_indent
143 (default: ``''``) String that will be prepended to all lines of wrapped
144 output except the first. Counts towards the length of each line except
148 .. attribute:: fix_sentence_endings
150 (default: ``False``) If true, :class:`TextWrapper` attempts to detect
151 sentence endings and ensure that sentences are always separated by exactly
152 two spaces. This is generally desired for text in a monospaced font.
153 However, the sentence detection algorithm is imperfect: it assumes that a
154 sentence ending consists of a lowercase letter followed by one of ``'.'``,
155 ``'!'``, or ``'?'``, possibly followed by one of ``'"'`` or ``"'"``,
156 followed by a space. One problem with this is algorithm is that it is
157 unable to detect the difference between "Dr." in ::
159 [...] Dr. Frankenstein's monster [...]
163 [...] See Spot. See Spot run [...]
165 :attr:`fix_sentence_endings` is false by default.
167 Since the sentence detection algorithm relies on ``string.lowercase`` for
168 the definition of "lowercase letter," and a convention of using two spaces
169 after a period to separate sentences on the same line, it is specific to
170 English-language texts.
173 .. attribute:: break_long_words
175 (default: ``True``) If true, then words longer than :attr:`width` will be
176 broken in order to ensure that no lines are longer than :attr:`width`. If
177 it is false, long words will not be broken, and some lines may be longer
178 than :attr:`width`. (Long words will be put on a line by themselves, in
179 order to minimize the amount by which :attr:`width` is exceeded.)
182 .. attribute:: break_on_hyphens
184 (default: ``True``) If true, wrapping will occur preferably on whitespaces
185 and right after hyphens in compound words, as it is customary in English.
186 If false, only whitespaces will be considered as potentially good places
187 for line breaks, but you need to set :attr:`break_long_words` to false if
188 you want truly insecable words. Default behaviour in previous versions
189 was to always allow breaking hyphenated words.
191 .. versionadded:: 2.6
194 :class:`TextWrapper` also provides two public methods, analogous to the
195 module-level convenience functions:
197 .. method:: wrap(text)
199 Wraps the single paragraph in *text* (a string) so every line is at most
200 :attr:`width` characters long. All wrapping options are taken from
201 instance attributes of the :class:`TextWrapper` instance. Returns a list
202 of output lines, without final newlines.
205 .. method:: fill(text)
207 Wraps the single paragraph in *text*, and returns a single string
208 containing the wrapped paragraph.