[External] : Use the characters "+" and "-" in regular expressions

[Christopher Dimech <dimech@gmx.com>]

This could be what you need

  (string-match "[\s]+ " s)

Matches any white-space character.

> Sent: Thursday, May 20, 2021 at 11:19 PM
> From: steve-humphreys@gmx.com
> To: tomas@tuxteam.de
> Cc: "help-gnu-emacs@gnu.org" <help-gnu-emacs@gnu.org>
> Subject: Re: [External] :  Use the characters "+" and "-" in regular expressions
>
> This is a string of blanks, a string composed of whitespace of any length.
>
> "                     "
>
>
>
> > Sent: Thursday, May 20, 2021 at 10:50 PM
> > From: tomas@tuxteam.de
> > To: steve-humphreys@gmx.com
> > Cc: "help-gnu-emacs@gnu.org" <help-gnu-emacs@gnu.org>
> > Subject: Re: [External] :  Use the characters "+" and "-" in regular expressions
> >
> > On Thu, May 20, 2021 at 12:37:17PM +0200, steve-humphreys@gmx.com wrote:
> >
> > [...]
> >
> > > Done some tests and got some strange results that thought would not match.  Then things
> > > made more sense after your clarification because when I looked at some of the strings,
> > > there was a comma in them.
> >
> > OK. Glad I could help.
> >
> > > Am seeing how to match strings of blank lines
> >
> > What is "a string of blank lines"?
> >
> > I know strings of characters. But a line is not a character.
> >
> > Do you mean "several blank lines next to each other"? I don't
> > think so. But what do you mean?
> >
> > > But " +" does not do the job.
> >
> > Again: you know by now that this will match "one or more spaces". Is
> > that for you a "string of blanks" (huh: where did you leave the
> > "line" from above?) or not?
> >
> > >                  I know why, but how can one match strings of blanks?
> >
> > To even have a chance to do that, you'll have to get hold of a more
> > or less precise idea of what "a string of blanks" is. This is work.
> >
> > Begin with:
> >
> >   (string-match " +" "A summer full of butterflies")
> >   => 1
> >
> > Bingo: the first run of one-or-more spaces is at the position 1
> > (the first position in the string is 0, the "A"). So it's working
> > as it should.
> >
> > So what is /your/ idea of "a string of blank lines" or "a string
> > of blanks"? Only you can find out.
> >
> > If you feel you are stuck in that task, it sometimes help to collect
> > a couple of examples and counter-examples (they'll come in handy
> > when you try to test your attempts).
> >
> > Cheers
> >  - t
> >
>
>