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Can I modify

> perl -E'@a= "# + 17 -18 +19 - 20 #" =~ /^ \# \s* ([+-] \s? \d+ \s+)* \# /xg; say qq(@a)'
> - 20

to capture all 4 numbers?

On Thu, 18 Aug 2011 06:25:57 -0700 (PDT), Wolfram Humann <> wrote:

>Can I modify
>
>> perl -E'@a= "# + 17 -18 +19 - 20 #" =~ /^ \# \s* ([+-] \s? \d+ \s+)* \# /xg; say qq(@a)'
>> - 20
>
>to capture all 4 numbers?

Not the way your doing it. There is no variable amount of
capture buffers. In c# they can do it your way. Normal pcre
can't do this.

You can however, validate the form, then capture the details...

perl -E "\"# + 17 -18 +19 - 20 #\" =~ /^\#\s*((?:[+-]\s?\d+\s+)*)\#/ and @a= $1 =~ /([+-]\s?\d+)\s+/g and say qq(@a)"
or
perl -E '"# + 17 -18 +19 - 20 #" =~ /^\#\s*((?:[+-]\s?\d+\s+)*)\#/ and @a= $1 =~ /([+-]\s?\d+)\s+/g and say qq(@a)'

-sln

>>>>> "WH" == Wolfram Humann <> writes:

WH> Can I modify

>> perl -E'@a= "# + 17 -18 +19 - 20 #" =~ /^ \# \s* ([+-] \s? \d+
>> \s+)* \# /xg; say qq(@a)' - 20

Yes. You can start by getting rid of the anchoring ^ and $ and #.

Charlton


--
Charlton Wilbur

In article
<7d42dfd1-68c0-4c1c-a6d4->,
Wolfram Humann <> wrote:

> Can I modify
>
> > perl -E'@a= "# + 17 -18 +19 - 20 #" =~ /^ \# \s* ([+-] \s? \d+ \s+)* \#
> > /xg; say qq(@a)'
> > - 20
>
> to capture all 4 numbers?
>

Yes. You need to remove the elements that anchor your pattern to the
beginning and end of the string, and eliminate the repeat modifier '*'
for the sub-pattern that matches the numbers:

perl -E'@a= ("# + 17 -18 +19 - 20 #" =~ /(\s* [+-] \s? \d+)/xg); say
qq(@a)'
+ 17 -18 +19 - 20

--
Jim Gibson

On Aug 18, 11:08*am, Jim Gibson <jimsgib...@gmail.com> wrote:
> In article
> <7d42dfd1-68c0-4c1c-a6d4-75344a11c...@x11g2000yqx.googlegroups.com>,
>
> Wolfram Humann <w.c.hum...@arcor.de> wrote:
> > Can I modify
>
> > > perl -E'@a= "# + 17 *-18 *+19 *- 20 #" =~ /^ \# \s* ([+-] \s? \d+ \s+)* \#
> > > /xg; say qq(@a)'
> > > - 20
>
> > to capture all 4 numbers?
>
> Yes. You need to remove the elements that anchor your pattern to the
> beginning and end of the string, and eliminate the repeat modifier '*'
> for the sub-pattern that matches the numbers:
>
> perl -E'@a= ("# + 17 *-18 *+19 *- 20 #" =~ /(\s* [+-] \s? \d+)/xg); say
> qq(@a)'
> *+ 17 * -18 * +19 * - 20

Or, it's slower but you could even
workaround the anchoring:

perl -E '@a= "# + 17 -18 +19 - 20 #" =~ /(?:^|) \#? \s* ([+-] \s?
\d+ \s+) \#? /xg; say qq(@a)'

--
Charles DeRykus

On Fri, 19 Aug 2011 13:42:37 -0700 (PDT), "C.DeRykus" <> wrote:

>On Aug 18, 11:08*am, Jim Gibson <jimsgib...@gmail.com> wrote:
>> In article
>> <7d42dfd1-68c0-4c1c-a6d4-75344a11c...@x11g2000yqx.googlegroups.com>,
>>
>> Wolfram Humann <w.c.hum...@arcor.de> wrote:
>> > Can I modify
>>
>> > > perl -E'@a= "# + 17 *-18 *+19 *- 20 #" =~ /^ \# \s* ([+-] \s? \d+ \s+)* \#
>> > > /xg; say qq(@a)'
>> > > - 20
>>
>> > to capture all 4 numbers?
>>
>> Yes. You need to remove the elements that anchor your pattern to the
>> beginning and end of the string, and eliminate the repeat modifier '*'
>> for the sub-pattern that matches the numbers:
>>
>> perl -E'@a= ("# + 17 *-18 *+19 *- 20 #" =~ /(\s* [+-] \s? \d+)/xg); say
>> qq(@a)'
>> *+ 17 * -18 * +19 * - 20
>
>Or, it's slower but you could even
>workaround the anchoring:
>
>perl -E '@a= "# + 17 -18 +19 - 20 #" =~ /(?:^|) \#? \s* ([+-] \s?
>\d+ \s+) \#? /xg; say qq(@a)'

Its meaningless that Wolfram used the /g modifier while anchoring the
regex with a must ^ unless it were used in conjunction with \G assertion.
So the anchors ^ and # would seem to be for validation of what must come
between. It would then be a wasted effort to exclude them, and at the
same time, a wasted effort to include them using /g in this context.

For capturing purposes,
/(?:^|) \#? \s* ([+-] \s? \d+ \s+) \#? /xg
is identical to
/([+-] \s? \d+ \s+)/xg

Both of which when applied to this string
"adfsg+ 17 *-18 dsfgh*92+19 *- 20 "
return the list
('+ 17 ', '-18 ', '+19 ', '- 20')

-sln

Thanks for the replies. Sorry I couldn't comment for the last couple
of days. Yes, the reason for the anchor is indeed that I want to both
validate (that I don't capture arbitrary numbers from *some* line) and
capture. Perhaps it's indeed better to separate those tasks. I was
aware that the /g was pretty useless here, but I thought it served
well to show what I *wanted* to do.

Thanks again,
Wolfram