Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1 | :mod:`textwrap` --- Text wrapping and filling |
| 2 | ============================================= |
| 3 | |
| 4 | .. module:: textwrap |
| 5 | :synopsis: Text wrapping and filling |
| 6 | .. moduleauthor:: Greg Ward <gward@python.net> |
| 7 | .. sectionauthor:: Greg Ward <gward@python.net> |
| 8 | |
Raymond Hettinger | 1048094 | 2011-01-10 03:26:08 +0000 | [diff] [blame] | 9 | **Source code:** :source:`Lib/textwrap.py` |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 10 | |
Raymond Hettinger | 4f707fd | 2011-01-10 19:54:11 +0000 | [diff] [blame] | 11 | -------------- |
| 12 | |
Antoine Pitrou | 389dec8 | 2013-08-12 22:39:09 +0200 | [diff] [blame] | 13 | The :mod:`textwrap` module provides some convenience functions, |
| 14 | as well as :class:`TextWrapper`, the class that does all the work. |
| 15 | If you're just wrapping or filling one or two text strings, the convenience |
| 16 | functions should be good enough; otherwise, you should use an instance of |
| 17 | :class:`TextWrapper` for efficiency. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 18 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 19 | .. function:: wrap(text, width=70, **kwargs) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 20 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 21 | Wraps the single paragraph in *text* (a string) so every line is at most |
| 22 | *width* characters long. Returns a list of output lines, without final |
| 23 | newlines. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 24 | |
| 25 | Optional keyword arguments correspond to the instance attributes of |
| 26 | :class:`TextWrapper`, documented below. *width* defaults to ``70``. |
| 27 | |
R David Murray | 1585b70 | 2012-09-08 13:13:25 -0400 | [diff] [blame] | 28 | See the :meth:`TextWrapper.wrap` method for additional details on how |
| 29 | :func:`wrap` behaves. |
| 30 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 31 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 32 | .. function:: fill(text, width=70, **kwargs) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 33 | |
| 34 | Wraps the single paragraph in *text*, and returns a single string containing the |
| 35 | wrapped paragraph. :func:`fill` is shorthand for :: |
| 36 | |
| 37 | "\n".join(wrap(text, ...)) |
| 38 | |
| 39 | In particular, :func:`fill` accepts exactly the same keyword arguments as |
| 40 | :func:`wrap`. |
| 41 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 42 | |
Antoine Pitrou | c593056 | 2013-08-16 22:31:12 +0200 | [diff] [blame] | 43 | .. function:: shorten(text, width=70, *, placeholder=" [...]") |
Alexandre Vassalotti | 5f8ced2 | 2008-05-16 00:03:33 +0000 | [diff] [blame] | 44 | |
Antoine Pitrou | 389dec8 | 2013-08-12 22:39:09 +0200 | [diff] [blame] | 45 | Collapse and truncate the given text to fit in the given width. |
| 46 | |
| 47 | The text first has its whitespace collapsed. If it then fits in |
| 48 | the *width*, it is returned unchanged. Otherwise, as many words |
| 49 | as possible are joined and then the *placeholder* is appended:: |
| 50 | |
| 51 | >>> textwrap.shorten("Hello world!", width=12) |
| 52 | 'Hello world!' |
| 53 | >>> textwrap.shorten("Hello world!", width=11) |
Antoine Pitrou | c593056 | 2013-08-16 22:31:12 +0200 | [diff] [blame] | 54 | 'Hello [...]' |
Antoine Pitrou | 389dec8 | 2013-08-12 22:39:09 +0200 | [diff] [blame] | 55 | >>> textwrap.shorten("Hello world", width=10, placeholder="...") |
| 56 | 'Hello...' |
| 57 | |
| 58 | .. versionadded:: 3.4 |
| 59 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 60 | |
| 61 | .. function:: dedent(text) |
| 62 | |
| 63 | Remove any common leading whitespace from every line in *text*. |
| 64 | |
| 65 | This can be used to make triple-quoted strings line up with the left edge of the |
| 66 | display, while still presenting them in the source code in indented form. |
| 67 | |
| 68 | Note that tabs and spaces are both treated as whitespace, but they are not |
| 69 | equal: the lines ``" hello"`` and ``"\thello"`` are considered to have no |
Georg Brandl | e6bcc91 | 2008-05-12 18:05:20 +0000 | [diff] [blame] | 70 | common leading whitespace. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 71 | |
| 72 | For example:: |
| 73 | |
| 74 | def test(): |
| 75 | # end first line with \ to avoid the empty line! |
| 76 | s = '''\ |
| 77 | hello |
| 78 | world |
| 79 | ''' |
Collin Winter | c79461b | 2007-09-01 23:34:30 +0000 | [diff] [blame] | 80 | print(repr(s)) # prints ' hello\n world\n ' |
| 81 | print(repr(dedent(s))) # prints 'hello\n world\n' |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 82 | |
| 83 | |
Nick Coghlan | 4fae8cd | 2012-06-11 23:07:51 +1000 | [diff] [blame] | 84 | .. function:: indent(text, prefix, predicate=None) |
| 85 | |
| 86 | Add *prefix* to the beginning of selected lines in *text*. |
| 87 | |
| 88 | Lines are separated by calling ``text.splitlines(True)``. |
| 89 | |
| 90 | By default, *prefix* is added to all lines that do not consist |
| 91 | solely of whitespace (including any line endings). |
| 92 | |
| 93 | For example:: |
| 94 | |
| 95 | >>> s = 'hello\n\n \nworld' |
| 96 | >>> indent(s, ' ') |
| 97 | ' hello\n\n \n world' |
| 98 | |
| 99 | The optional *predicate* argument can be used to control which lines |
| 100 | are indented. For example, it is easy to add *prefix* to even empty |
| 101 | and whitespace-only lines:: |
| 102 | |
| 103 | >>> print(indent(s, '+ ', lambda line: True)) |
| 104 | + hello |
| 105 | + |
| 106 | + |
| 107 | + world |
| 108 | |
| 109 | |
Antoine Pitrou | 389dec8 | 2013-08-12 22:39:09 +0200 | [diff] [blame] | 110 | :func:`wrap`, :func:`fill` and :func:`shorten` work by creating a |
| 111 | :class:`TextWrapper` instance and calling a single method on it. That |
| 112 | instance is not reused, so for applications that process many text |
| 113 | strings, it may be more efficient to create your own |
| 114 | :class:`TextWrapper` object. |
| 115 | |
| 116 | Text is preferably wrapped on whitespaces and right after the hyphens in |
| 117 | hyphenated words; only then will long words be broken if necessary, unless |
| 118 | :attr:`TextWrapper.break_long_words` is set to false. |
| 119 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 120 | .. class:: TextWrapper(**kwargs) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 121 | |
| 122 | The :class:`TextWrapper` constructor accepts a number of optional keyword |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 123 | arguments. Each keyword argument corresponds to an instance attribute, so |
| 124 | for example :: |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 125 | |
| 126 | wrapper = TextWrapper(initial_indent="* ") |
| 127 | |
| 128 | is the same as :: |
| 129 | |
| 130 | wrapper = TextWrapper() |
| 131 | wrapper.initial_indent = "* " |
| 132 | |
| 133 | You can re-use the same :class:`TextWrapper` object many times, and you can |
| 134 | change any of its options through direct assignment to instance attributes |
| 135 | between uses. |
| 136 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 137 | The :class:`TextWrapper` instance attributes (and keyword arguments to the |
| 138 | constructor) are as follows: |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 139 | |
| 140 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 141 | .. attribute:: width |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 142 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 143 | (default: ``70``) The maximum length of wrapped lines. As long as there |
| 144 | are no individual words in the input text longer than :attr:`width`, |
| 145 | :class:`TextWrapper` guarantees that no output line will be longer than |
| 146 | :attr:`width` characters. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 147 | |
| 148 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 149 | .. attribute:: expand_tabs |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 150 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 151 | (default: ``True``) If true, then all tab characters in *text* will be |
| 152 | expanded to spaces using the :meth:`expandtabs` method of *text*. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 153 | |
| 154 | |
Hynek Schlawack | d527259 | 2012-05-19 13:33:11 +0200 | [diff] [blame] | 155 | .. attribute:: tabsize |
| 156 | |
| 157 | (default: ``8``) If :attr:`expand_tabs` is true, then all tab characters |
| 158 | in *text* will be expanded to zero or more spaces, depending on the |
| 159 | current column and the given tab size. |
| 160 | |
| 161 | .. versionadded:: 3.3 |
| 162 | |
| 163 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 164 | .. attribute:: replace_whitespace |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 165 | |
Andrew Svetlov | 59db401 | 2012-08-13 23:22:23 +0300 | [diff] [blame] | 166 | (default: ``True``) If true, after tab expansion but before wrapping, |
| 167 | the :meth:`wrap` method will replace each whitespace character |
| 168 | with a single space. The whitespace characters replaced are |
| 169 | as follows: tab, newline, vertical tab, formfeed, and carriage |
| 170 | return (``'\t\n\v\f\r'``). |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 171 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 172 | .. note:: |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 173 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 174 | If :attr:`expand_tabs` is false and :attr:`replace_whitespace` is true, |
| 175 | each tab character will be replaced by a single space, which is *not* |
| 176 | the same as tab expansion. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 177 | |
Terry Reedy | 6d2ab71 | 2010-11-23 20:17:24 +0000 | [diff] [blame] | 178 | .. note:: |
| 179 | |
| 180 | If :attr:`replace_whitespace` is false, newlines may appear in the |
| 181 | middle of a line and cause strange output. For this reason, text should |
| 182 | be split into paragraphs (using :meth:`str.splitlines` or similar) |
| 183 | which are wrapped separately. |
| 184 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 185 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 186 | .. attribute:: drop_whitespace |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 187 | |
R David Murray | 1585b70 | 2012-09-08 13:13:25 -0400 | [diff] [blame] | 188 | (default: ``True``) If true, whitespace at the beginning and ending of |
| 189 | every line (after wrapping but before indenting) is dropped. |
| 190 | Whitespace at the beginning of the paragraph, however, is not dropped |
| 191 | if non-whitespace follows it. If whitespace being dropped takes up an |
| 192 | entire line, the whole line is dropped. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 193 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 194 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 195 | .. attribute:: initial_indent |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 196 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 197 | (default: ``''``) String that will be prepended to the first line of |
R David Murray | 1585b70 | 2012-09-08 13:13:25 -0400 | [diff] [blame] | 198 | wrapped output. Counts towards the length of the first line. The empty |
| 199 | string is not indented. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 200 | |
| 201 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 202 | .. attribute:: subsequent_indent |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 203 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 204 | (default: ``''``) String that will be prepended to all lines of wrapped |
| 205 | output except the first. Counts towards the length of each line except |
| 206 | the first. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 207 | |
| 208 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 209 | .. attribute:: fix_sentence_endings |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 210 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 211 | (default: ``False``) If true, :class:`TextWrapper` attempts to detect |
| 212 | sentence endings and ensure that sentences are always separated by exactly |
| 213 | two spaces. This is generally desired for text in a monospaced font. |
| 214 | However, the sentence detection algorithm is imperfect: it assumes that a |
| 215 | sentence ending consists of a lowercase letter followed by one of ``'.'``, |
| 216 | ``'!'``, or ``'?'``, possibly followed by one of ``'"'`` or ``"'"``, |
| 217 | followed by a space. One problem with this is algorithm is that it is |
| 218 | unable to detect the difference between "Dr." in :: |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 219 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 220 | [...] Dr. Frankenstein's monster [...] |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 221 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 222 | and "Spot." in :: |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 223 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 224 | [...] See Spot. See Spot run [...] |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 225 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 226 | :attr:`fix_sentence_endings` is false by default. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 227 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 228 | Since the sentence detection algorithm relies on ``string.lowercase`` for |
| 229 | the definition of "lowercase letter," and a convention of using two spaces |
| 230 | after a period to separate sentences on the same line, it is specific to |
| 231 | English-language texts. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 232 | |
| 233 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 234 | .. attribute:: break_long_words |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 235 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 236 | (default: ``True``) If true, then words longer than :attr:`width` will be |
| 237 | broken in order to ensure that no lines are longer than :attr:`width`. If |
| 238 | it is false, long words will not be broken, and some lines may be longer |
| 239 | than :attr:`width`. (Long words will be put on a line by themselves, in |
| 240 | order to minimize the amount by which :attr:`width` is exceeded.) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 241 | |
Alexandre Vassalotti | 5f8ced2 | 2008-05-16 00:03:33 +0000 | [diff] [blame] | 242 | |
| 243 | .. attribute:: break_on_hyphens |
| 244 | |
| 245 | (default: ``True``) If true, wrapping will occur preferably on whitespaces |
| 246 | and right after hyphens in compound words, as it is customary in English. |
| 247 | If false, only whitespaces will be considered as potentially good places |
| 248 | for line breaks, but you need to set :attr:`break_long_words` to false if |
| 249 | you want truly insecable words. Default behaviour in previous versions |
| 250 | was to always allow breaking hyphenated words. |
| 251 | |
Alexandre Vassalotti | 5f8ced2 | 2008-05-16 00:03:33 +0000 | [diff] [blame] | 252 | |
Serhiy Storchaka | acc9f3f | 2013-10-15 21:22:54 +0300 | [diff] [blame^] | 253 | .. attribute:: max_lines |
| 254 | |
| 255 | (default: ``None``) If not ``None``, then the text be will truncated to |
| 256 | *max_lines* lines. |
| 257 | |
| 258 | .. versionadded:: 3.4 |
| 259 | |
| 260 | |
| 261 | .. attribute:: placeholder |
| 262 | |
| 263 | (default: ``' [...]'``) String that will be appended to the last line of |
| 264 | text if it will be truncated. |
| 265 | |
| 266 | .. versionadded:: 3.4 |
| 267 | |
| 268 | |
Antoine Pitrou | 389dec8 | 2013-08-12 22:39:09 +0200 | [diff] [blame] | 269 | :class:`TextWrapper` also provides some public methods, analogous to the |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 270 | module-level convenience functions: |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 271 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 272 | .. method:: wrap(text) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 273 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 274 | Wraps the single paragraph in *text* (a string) so every line is at most |
| 275 | :attr:`width` characters long. All wrapping options are taken from |
R David Murray | 1585b70 | 2012-09-08 13:13:25 -0400 | [diff] [blame] | 276 | instance attributes of the :class:`TextWrapper` instance. Returns a list |
| 277 | of output lines, without final newlines. If the wrapped output has no |
| 278 | content, the returned list is empty. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 279 | |
| 280 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 281 | .. method:: fill(text) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 282 | |
Benjamin Peterson | e41251e | 2008-04-25 01:59:09 +0000 | [diff] [blame] | 283 | Wraps the single paragraph in *text*, and returns a single string |
| 284 | containing the wrapped paragraph. |