bpo-30021: Add examples for re.escape(). (#1048) (#1116)

And fix the parameter name.

(cherry picked from commit 8fc7bc2b7631ee819ee614e47b6f44bacebe1574)

1 files changed, 14 insertions, 3 deletions

diff --git a/Doc/library/re.rst b/Doc/library/re.rst
index 6baac6f..d33fff8 100644
--- a/Doc/library/re.rst
+++ b/Doc/library/re.rst
@@ -771,11 +771,22 @@ form.
       Unmatched groups are replaced with an empty string.
 
 
-.. function:: escape(string)
+.. function:: escape(pattern)
 
-   Escape all the characters in pattern except ASCII letters, numbers and ``'_'``.
+   Escape all the characters in *pattern* except ASCII letters, numbers and ``'_'``.
    This is useful if you want to match an arbitrary literal string that may
-   have regular expression metacharacters in it.
+   have regular expression metacharacters in it.  For example::
+
+      >>> print(re.escape('python.exe'))
+      python\.exe
+
+      >>> legal_chars = string.ascii_lowercase + string.digits + "!#$%&'*+-.^_`|~:"
+      >>> print('[%s]+' % re.escape(legal_chars))
+      [abcdefghijklmnopqrstuvwxyz0123456789\!\#\$\%\&\'\*\+\-\.\^_\`\|\~\:]+
+
+      >>> operators = ['+', '-', '*', '/', '**']
+      >>> print('|'.join(map(re.escape, sorted(operators, reverse=True))))
+      \/|\-|\+|\*\*|\*
 
    .. versionchanged:: 3.3
       The ``'_'`` character is no longer escaped.