:mod:`!textwrap` --- Text wrapping and filling

.. module:: textwrap :synopsis: Text wrapping and filling

Source code: :source:Lib/textwrap.py

The :mod:!textwrap module provides some convenience functions, as well as :class:TextWrapper, the class that does all the work. If you're just wrapping or filling one or two text strings, the convenience functions should be good enough; otherwise, you should use an instance of :class:TextWrapper for efficiency.

.. function:: wrap(text, width=70, *, initial_indent="",
subsequent_indent="", expand_tabs=True,
replace_whitespace=True, fix_sentence_endings=False,
break_long_words=True, drop_whitespace=True,
break_on_hyphens=True, tabsize=8, max_lines=None,
placeholder=' [...]')

Wraps the single paragraph in text (a string) so every line is at most width characters long. Returns a list of output lines, without final newlines.

Optional keyword arguments correspond to the instance attributes of :class:TextWrapper, documented below.

See the :meth:TextWrapper.wrap method for additional details on how :func:wrap behaves.

.. function:: fill(text, width=70, *, initial_indent="",
subsequent_indent="", expand_tabs=True,
replace_whitespace=True, fix_sentence_endings=False,
break_long_words=True, drop_whitespace=True,
break_on_hyphens=True, tabsize=8,
max_lines=None, placeholder=' [...]')

Wraps the single paragraph in text, and returns a single string containing the wrapped paragraph. :func:fill is shorthand for ::

  "\n".join(wrap(text, ...))

In particular, :func:fill accepts exactly the same keyword arguments as :func:wrap.

.. function:: shorten(text, width, *, fix_sentence_endings=False,
break_long_words=True, break_on_hyphens=True,
placeholder=' [...]')

Collapse and truncate the given text to fit in the given width.

First the whitespace in text is collapsed (all whitespace is replaced by single spaces). If the result fits in the width, it is returned. Otherwise, enough words are dropped from the end so that the remaining words plus the placeholder fit within width::

  >>> textwrap.shorten("Hello  world!", width=12)
  'Hello world!'
  >>> textwrap.shorten("Hello  world!", width=11)
  'Hello [...]'
  >>> textwrap.shorten("Hello world", width=10, placeholder="...")
  'Hello...'

Optional keyword arguments correspond to the instance attributes of :class:TextWrapper, documented below. Note that the whitespace is collapsed before the text is passed to the :class:TextWrapper :meth:fill function, so changing the value of :attr:.tabsize, :attr:.expand_tabs, :attr:.drop_whitespace, and :attr:.replace_whitespace will have no effect.

.. versionadded:: 3.4

.. function:: dedent(text)

Remove any common leading whitespace from every line in text.

This can be used to make triple-quoted strings line up with the left edge of the display, while still presenting them in the source code in indented form.

Note that tabs and spaces are both treated as whitespace, but they are not equal: the lines " hello" and "\thello" are considered to have no common leading whitespace.

Lines containing only whitespace are ignored in the input and normalized to a single newline character in the output.

For example::

  def test():
      # end first line with \ to avoid the empty line!
      s = '''\
      hello
        world
      '''
      print(repr(s))          # prints '    hello\n      world\n    '
      print(repr(dedent(s)))  # prints 'hello\n  world\n'

.. versionchanged:: 3.14 The :func:!dedent function now correctly normalizes blank lines containing only whitespace characters. Previously, the implementation only normalized blank lines containing tabs and spaces.

.. function:: indent(text, prefix, predicate=None)

Add prefix to the beginning of selected lines in text.

Lines are separated by calling text.splitlines(True).

By default, prefix is added to all lines that do not consist solely of whitespace (including any line endings).

For example::

  >>> s = 'hello\n\n \nworld'
  >>> indent(s, '  ')
  '  hello\n\n \n  world'

The optional predicate argument can be used to control which lines are indented. For example, it is easy to add prefix to even empty and whitespace-only lines::

  >>> print(indent(s, '+ ', lambda line: True))
  + hello
  +
  +
  + world

.. versionadded:: 3.3

:func:wrap, :func:fill and :func:shorten work by creating a :class:TextWrapper instance and calling a single method on it. That instance is not reused, so for applications that process many text strings using :func:wrap and/or :func:fill, it may be more efficient to create your own :class:TextWrapper object.

Text is preferably wrapped on whitespaces and right after the hyphens in hyphenated words; only then will long words be broken if necessary, unless :attr:TextWrapper.break_long_words is set to false.

.. class:: TextWrapper(**kwargs)

The :class:TextWrapper constructor accepts a number of optional keyword arguments. Each keyword argument corresponds to an instance attribute, so for example ::

  wrapper = TextWrapper(initial_indent="* ")

is the same as ::

  wrapper = TextWrapper()
  wrapper.initial_indent = "* "

You can reuse the same :class:TextWrapper object many times, and you can change any of its options through direct assignment to instance attributes between uses.

The :class:TextWrapper instance attributes (and keyword arguments to the constructor) are as follows:

.. attribute:: width

  (default: ``70``) The maximum length of wrapped lines.  As long as there
  are no individual words in the input text longer than :attr:`width`,
  :class:`TextWrapper` guarantees that no output line will be longer than
  :attr:`width` characters.

.. attribute:: expand_tabs

  (default: ``True``) If true, then all tab characters in *text* will be
  expanded to spaces using the :meth:`~str.expandtabs` method of *text*.

.. attribute:: tabsize

  (default: ``8``) If :attr:`expand_tabs` is true, then all tab characters
  in *text* will be expanded to zero or more spaces, depending on the
  current column and the given tab size.

  .. versionadded:: 3.3

.. attribute:: replace_whitespace

  (default: ``True``) If true, after tab expansion but before wrapping,
  the :meth:`wrap` method will replace each whitespace character
  with a single space.  The whitespace characters replaced are
  as follows: tab, newline, vertical tab, formfeed, and carriage
  return (``'\t\n\v\f\r'``).

  .. note::

     If :attr:`expand_tabs` is false and :attr:`replace_whitespace` is true,
     each tab character will be replaced by a single space, which is *not*
     the same as tab expansion.

  .. note::

     If :attr:`replace_whitespace` is false, newlines may appear in the
     middle of a line and cause strange output. For this reason, text should
     be split into paragraphs (using :meth:`str.splitlines` or similar)
     which are wrapped separately.

.. attribute:: drop_whitespace

  (default: ``True``) If true, whitespace at the beginning and ending of
  every line (after wrapping but before indenting) is dropped.
  Whitespace at the beginning of the paragraph, however, is not dropped
  if non-whitespace follows it.  If whitespace being dropped takes up an
  entire line, the whole line is dropped.

.. attribute:: initial_indent

  (default: ``''``) String that will be prepended to the first line of
  wrapped output.  Counts towards the length of the first line.  The empty
  string is not indented.

.. attribute:: subsequent_indent

  (default: ``''``) String that will be prepended to all lines of wrapped
  output except the first.  Counts towards the length of each line except
  the first.

.. attribute:: fix_sentence_endings

  (default: ``False``) If true, :class:`TextWrapper` attempts to detect
  sentence endings and ensure that sentences are always separated by exactly
  two spaces.  This is generally desired for text in a monospaced font.
  However, the sentence detection algorithm is imperfect: it assumes that a
  sentence ending consists of a lowercase letter followed by one of ``'.'``,
  ``'!'``, or ``'?'``, possibly followed by one of ``'"'`` or ``"'"``,
  followed by a space.  One problem with this algorithm is that it is
  unable to detect the difference between "Dr." in ::

     [...] Dr. Frankenstein's monster [...]

  and "Spot." in ::

     [...] See Spot. See Spot run [...]

  :attr:`fix_sentence_endings` is false by default.

  Since the sentence detection algorithm relies on ``string.lowercase`` for
  the definition of "lowercase letter", and a convention of using two spaces
  after a period to separate sentences on the same line, it is specific to
  English-language texts.

.. attribute:: break_long_words

  (default: ``True``) If true, then words longer than :attr:`width` will be
  broken in order to ensure that no lines are longer than :attr:`width`.  If
  it is false, long words will not be broken, and some lines may be longer
  than :attr:`width`.  (Long words will be put on a line by themselves, in
  order to minimize the amount by which :attr:`width` is exceeded.)

.. attribute:: break_on_hyphens

  (default: ``True``) If true, wrapping will occur preferably on whitespaces
  and right after hyphens in compound words, as it is customary in English.
  If false, only whitespaces will be considered as potentially good places
  for line breaks, but you need to set :attr:`break_long_words` to false if
  you want truly insecable words.  Default behaviour in previous versions
  was to always allow breaking hyphenated words.

.. attribute:: max_lines

  (default: ``None``) If not ``None``, then the output will contain at most
  *max_lines* lines, with *placeholder* appearing at the end of the output.

  .. versionadded:: 3.4

.. index:: single: ...; placeholder

.. attribute:: placeholder

  (default: ``' [...]'``) String that will appear at the end of the output
  text if it has been truncated.

  .. versionadded:: 3.4

:class:TextWrapper also provides some public methods, analogous to the module-level convenience functions:

.. method:: wrap(text)

  Wraps the single paragraph in *text* (a string) so every line is at most
  :attr:`width` characters long.  All wrapping options are taken from
  instance attributes of the :class:`TextWrapper` instance.  Returns a list
  of output lines, without final newlines.  If the wrapped output has no
  content, the returned list is empty.

.. method:: fill(text)

  Wraps the single paragraph in *text*, and returns a single string
  containing the wrapped paragraph.

:mod:`!textwrap` --- Text wrapping and filling

:mod:!textwrap --- Text wrapping and filling

:mod:`!textwrap` --- Text wrapping and filling