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?
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(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. The power of regexps stems from the ability to mix and match all of the regexp pieces in pretty much any way you want. -- Devin -- https://mail.python.org/mailman/listinfo/python-list
