In related news, the regexp I gave for numbers will match "1a". -- Devin
On Sun, Jul 6, 2014 at 8:32 AM, MRAB <pyt...@mrabarnett.plus.com> wrote: > On 2014-07-06 13:09, Devin Jeanpierre wrote: >> >> On Sun, Jul 6, 2014 at 4:51 AM, <rxjw...@gmail.com> wrote: >>> >>> Hi, >>> >>> I just begin to learn Python. I do not see the usefulness of '*' in its >>> description below: >>> >>> >>> >>> >>> The first metacharacter for repeating things that we'll look at is *. * >>> doesn't >>> match the literal character *; instead, it specifies that the previous >>> character >>> can be matched zero or more times, instead of exactly once. >>> >>> For example, ca*t will match ct (0 a characters), cat (1 a), caaat (3 a >>> characters), and so forth. >>> >>> >>> >>> It has to be used with other search constraints? >> >> >> (BTW, this is a regexp question, not really a Python question per se.) >> >> That's usually when it's useful, yeah. For example, [0-9] matches any >> of the characters 0 through 9. So to match a natural number written in >> decimal form, we might use the regexp [0-9][0-9]*, which matches the >> strings "1", "12", and "007", but not "" or "Jeffrey". >> >> Another useful one is `.*` -- `.` matches exactly one character, no >> matter what that character is. So, `.*` matches any string at all. >> > Not quite. It won't match a '\n' unless the DOTALL flag is turned on. > > >> The power of regexps stems from the ability to mix and match all of >> the regexp pieces in pretty much any way you want. >> > > -- > https://mail.python.org/mailman/listinfo/python-list -- https://mail.python.org/mailman/listinfo/python-list
