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Re: [NTS] Re: NTB or RegEx Bug

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  • Axel Berger
    ... I think in practice a star quantifier on its own is meaningless, there must be at least one other thing in the pattern. If you re interested in one
    Message 1 of 11 , Sep 29, 2012
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      "flo.gehrke" wrote:
      > You could use 'a*a' instead of 'a*'.

      I think in practice a star quantifier on its own is meaningless, there
      must be at least one other thing in the pattern. If you're interested in
      one character only, then the quantifier has to be at least "+". All
      Art's "a*x" examples worked fine and so do all cases where I use the "*"
      or "?" quantifier.
      What can the possible use be for something that matches anywhere in
      anything?

      Axel
    • flo.gehrke
      ... In this context, I understood that a is just an element that, in practice , would primarily represent an element in a more complex pattern. In this
      Message 2 of 11 , Sep 30, 2012
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        --- In ntb-scripts@yahoogroups.com, Axel Berger <Axel-Berger@...> wrote:
        >
        > "flo.gehrke" wrote:
        > > You could use 'a*a' instead of 'a*'.
        > I think in practice a star quantifier on its own is
        > meaningless, there must be at least one other thing in the
        > pattern...What can the possible use be for something that
        > matches anywhere in anything?

        In this context, I understood that 'a' is just an element that, "in practice", would primarily represent an element in a more complex pattern. In this respect, I agree with the objection you made.

        In order to match just a sequence of literal 'a', a pattern like 'a*a' wouldn't make much sense, indeed. And 'a{1,}' or 'a+' would certainly be more appropriate solutions.

        But to prevent any misunderstanding among beginners, we should stress that something like 'a*' is not at all useless under ANY circumstances. Quite often, we have to define that an element 'a' is there or it is not there.

        For example: (?<=<xxx>)\d*(?=</xxx>) matching the position between '>' and '<' in strings like...

        <xxx>12</xxx>
        <xxx></xxx>
        <xxx>9</xxx>

        no matter if there is a number or no number.

        Regards,
        Flo
      • John Shotsky
        I agree, and use the star heavily in my clip libraries. Regards, John RecipeTools Web Site: http://recipetools.gotdns.com/
        Message 3 of 11 , Sep 30, 2012
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          I agree, and use the star heavily in my clip libraries.

          Regards,
          John
          RecipeTools Web Site: <http://recipetools.gotdns.com/> http://recipetools.gotdns.com/

          From: ntb-scripts@yahoogroups.com [mailto:ntb-scripts@yahoogroups.com] On Behalf Of flo.gehrke
          Sent: Sunday, September 30, 2012 05:39
          To: ntb-scripts@yahoogroups.com
          Subject: [NTS] Re: NTB or RegEx Bug


          --- In ntb-scripts@yahoogroups.com <mailto:ntb-scripts%40yahoogroups.com> , Axel Berger <Axel-Berger@...> wrote:
          >
          > "flo.gehrke" wrote:
          > > You could use 'a*a' instead of 'a*'.
          > I think in practice a star quantifier on its own is
          > meaningless, there must be at least one other thing in the
          > pattern...What can the possible use be for something that
          > matches anywhere in anything?

          In this context, I understood that 'a' is just an element that, "in practice", would primarily represent an element in a
          more complex pattern. In this respect, I agree with the objection you made.

          In order to match just a sequence of literal 'a', a pattern like 'a*a' wouldn't make much sense, indeed. And 'a{1,}' or
          'a+' would certainly be more appropriate solutions.

          But to prevent any misunderstanding among beginners, we should stress that something like 'a*' is not at all useless
          under ANY circumstances. Quite often, we have to define that an element 'a' is there or it is not there.

          For example: (?<=<xxx>)\d*(?=</xxx>) matching the position between '>' and '<' in strings like...

          <xxx>12</xxx>
          <xxx></xxx>
          <xxx>9</xxx>

          no matter if there is a number or no number.

          Regards,
          Flo



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