[32474] in Perl-Users-Digest
Perl-Users Digest, Issue: 3739 Volume: 11
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Sat Jul 21 03:09:29 2012
Date: Sat, 21 Jul 2012 00:09:05 -0700 (PDT)
From: Perl-Users Digest <Perl-Users-Request@ruby.OCE.ORST.EDU>
To: Perl-Users@ruby.OCE.ORST.EDU (Perl-Users Digest)
Perl-Users Digest Sat, 21 Jul 2012 Volume: 11 Number: 3739
Today's topics:
Re: easiest way to set $1 $2 $3... (Seymour J.)
Re: easiest way to set $1 $2 $3... (Randal L. Schwartz)
elegant way of getting last REAL value of an array <cartercc@gmail.com>
Re: elegant way of getting last REAL value of an array <NoSpamPleaseButThisIsValid3@gmx.net>
Re: elegant way of getting last REAL value of an array <cartercc@gmail.com>
Re: elegant way of getting last REAL value of an array <rweikusat@mssgmbh.com>
Re: elegant way of getting last REAL value of an array <rweikusat@mssgmbh.com>
Re: elegant way of getting last REAL value of an array <cartercc@gmail.com>
Flushing and multiple pipes <lelli.luca@googlemail.com>
Re: Flushing and multiple pipes <rweikusat@mssgmbh.com>
Re: Flushing and multiple pipes <lelli.luca@googlemail.com>
Help needed to finding how many users are in a group.. clearguy02@yahoo.com
Re: Help needed to finding how many users are in a grou <rweikusat@mssgmbh.com>
Re: Help needed to finding how many users are in a grou clearguy02@yahoo.com
Re: Help needed to finding how many users are in a grou <jurgenex@hotmail.com>
Re: Help needed to finding how many users are in a grou <jimsgibson@gmail.com>
Re: Help needed to finding how many users are in a grou <rweikusat@mssgmbh.com>
Re: LibXML element->toString vs document->toString (Seymour J.)
Re: Regex: match double OR single quote (Seymour J.)
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Thu, 19 Jul 2012 10:40:14 -0400
From: Shmuel (Seymour J.) Metz <spamtrap@library.lspace.org.invalid>
Subject: Re: easiest way to set $1 $2 $3...
Message-Id: <50081c4e$1$fuzhry+tra$mr2ice@news.patriot.net>
In <ju5vf7$ah$1@news.datemas.de>, on 07/18/2012
at 05:25 PM, jidanni@jidanni.org said:
>So what is the easiest way to do the same in perl?
An assignment in array context.
>No don't ask me why I want to set them,
Why not? You're almost certainly asking the wrong question.
>If it takes more than just a one-liner, then perl has problems.
Only if it's something that programmers need to do frequently, which
it is not.
>$ perl -wle '"abc" =~ /(.)(.)(.)/; print $1, $2, $3;'
Looks normal.
>Big drag.
Why?
>So we see on perlvar there is no array that can give us even
>read-only access to
> $<digits> ($1, $2, ...)
Who cares? There's also no array to give even read-only access to $_,
$&, and $/.
>not of course even to think of an easy way to set them by all
>directly by hand if we need to.
Of course there's an easy way, but it's pointless.
>Well maybe perlvar should mention what the best way so-far to access
>them all (like /bin/sh's $@, $*), and set them all (like /bin/sh's
>set) is!
If there were a point to it and it was relevant to perlvar then yes,
but since there isn't and it isn't then no.
--
Shmuel (Seymour J.) Metz, SysProg and JOAT <http://patriot.net/~shmuel>
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right to publicly post or ridicule any abusive E-mail. Reply to
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------------------------------
Date: Thu, 19 Jul 2012 08:45:54 -0700
From: merlyn@stonehenge.com (Randal L. Schwartz)
Subject: Re: easiest way to set $1 $2 $3...
Message-Id: <86394nkb4d.fsf@red.stonehenge.com>
>>>>> "Shmuel" == Shmuel (Seymour J ) Metz <spamtrap@library.lspace.org.invalid> writes:
Shmuel> An assignment in array context.
*list* context. "wantarray" is misnamed.
--
Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
<merlyn@stonehenge.com> <URL:http://www.stonehenge.com/merlyn/>
Smalltalk/Perl/Unix consulting, Technical writing, Comedy, etc. etc.
See http://methodsandmessages.posterous.com/ for Smalltalk discussion
------------------------------
Date: Thu, 19 Jul 2012 09:11:34 -0700 (PDT)
From: ccc31807 <cartercc@gmail.com>
Subject: elegant way of getting last REAL value of an array
Message-Id: <cd75d5ce-1810-46f8-93a9-d81f47c337b4@u20g2000yqk.googlegroups.com>
I have three values that may or may not contain values, call them
$grad1, $grad2, and $grad3. The values they may contain are dates,
like this: 04/12.
My current code munges them like this:
my $grad = ""; # if there are no dates
$grad = $grad1 if $grad1 =~ /\d\d/;
$grad = $grad2 if $grad2 =~ /\d\d/;
$grad = $grad3 if $grad3 =~ /\d\d/;
What I might like to do is this:
my @grad = ($grad1, $grad2, $grad3);
my $grad = ??? #either the last value of @grad that matches /\d\d/ or
"" if none does
Maybe it's a mental block, but I can't figure out how to do this.
Ideas?
Thanks, CC.
------------------------------
Date: Thu, 19 Jul 2012 18:35:13 +0200
From: Wolf Behrenhoff <NoSpamPleaseButThisIsValid3@gmx.net>
Subject: Re: elegant way of getting last REAL value of an array
Message-Id: <50083742$0$9520$9b4e6d93@newsspool1.arcor-online.net>
Am 19.07.2012 18:11, schrieb ccc31807:
> I have three values that may or may not contain values, call them
> $grad1, $grad2, and $grad3. The values they may contain are dates,
> like this: 04/12.
>
> What I might like to do is this:
> my @grad = ($grad1, $grad2, $grad3);
> my $grad = ??? #either the last value of @grad that matches /\d\d/ or
> "" if none does
>
> Maybe it's a mental block, but I can't figure out how to do this.
Using the List::Util module:
use List::Util qw(first);
my @dates=qw(abc 01/02 02/03 de);
say first {/\d\d/} reverse @g'
- Wolf
------------------------------
Date: Thu, 19 Jul 2012 09:41:27 -0700 (PDT)
From: ccc31807 <cartercc@gmail.com>
Subject: Re: elegant way of getting last REAL value of an array
Message-Id: <bc8107c6-8be1-4755-be62-8cc10be18d33@j4g2000yqj.googlegroups.com>
On Jul 19, 12:35=A0pm, Wolf Behrenhoff
<NoSpamPleaseButThisIsVal...@gmx.net> wrote:
> use List::Util qw(first);
> my @dates=3Dqw(abc 01/02 02/03 de);
> say first {/\d\d/} reverse @g'
Yep, exactly right. Passing reverse(@g) to first() is a nice touch.
Thanks, CC.
------------------------------
Date: Thu, 19 Jul 2012 18:42:12 +0100
From: Rainer Weikusat <rweikusat@mssgmbh.com>
Subject: Re: elegant way of getting last REAL value of an array
Message-Id: <87d33rwsuj.fsf@sapphire.mobileactivedefense.com>
ccc31807 <cartercc@gmail.com> writes:
> On Jul 19, 12:35 pm, Wolf Behrenhoff
> <NoSpamPleaseButThisIsVal...@gmx.net> wrote:
>> use List::Util qw(first);
>> my @dates=qw(abc 01/02 02/03 de);
>> say first {/\d\d/} reverse @g'
>
> Yep, exactly right. Passing reverse(@g) to first() is a nice touch.
The same can be achieved with just about as little code without
loading an additional module and performing several subroutine calls
and even without creating the intermediate reverted list
------------
use Benchmark;
use List::Util qw(first);
my @g = qw(ab 02 03 ee);
timethese(-10,
{
first => sub {
return first {/\d\d/} reverse(@g);
},
inline => sub {
my $g;
/\d\d/ and $g = $_, last for reverse(@g);
return $g;
},
inplace => sub {
my ($g, $n);
$n = @g;
{ $g[--$n] =~ /\d\d/ and $g = $g[$n], last while ($n--); }
return $g;
}});
------------
[The additional block in the last sub is necessary because last works
with a for-modifier but doesn't work with while-modifier/ 5.10.1]
------------------------------
Date: Thu, 19 Jul 2012 18:51:39 +0100
From: Rainer Weikusat <rweikusat@mssgmbh.com>
Subject: Re: elegant way of getting last REAL value of an array
Message-Id: <878vefwses.fsf@sapphire.mobileactivedefense.com>
Rainer Weikusat <rweikusat@mssgmbh.com> writes:
[...]
> { $g[--$n] =~ /\d\d/ and $g = $g[$n], last while ($n--); }
The [--$n] was left-over from a slightly different variant and must
not actually be there.
------------------------------
Date: Thu, 19 Jul 2012 11:14:22 -0700 (PDT)
From: ccc31807 <cartercc@gmail.com>
Subject: Re: elegant way of getting last REAL value of an array
Message-Id: <1b5730c7-c4a0-4661-9be5-04f177ba81f4@d32g2000yqn.googlegroups.com>
On Jul 19, 1:42=A0pm, Rainer Weikusat <rweiku...@mssgmbh.com> wrote:
> The same can be achieved with just about as little code without
> loading an additional module and performing several subroutine calls
> and even without creating the intermediate reverted list
I am picking these three values from a CSV file, which contains
several other array-types of things, e.g. email addresses and phone
numbers, that I can sift through with regular expressions. The
particular problem I had was that I have several dates in exactly the
same format. All of these consist of exactly one value, except for
this particular one. What I get from the database is an indeterminate
list of possible values, which number I limit to 3 after looking at
the data.
The insight I missed was simply reversing the list. It's so obvious
now that I'll a little embarrassed that I missed it.
Thanks for your suggestion, CC.
------------------------------
Date: Fri, 20 Jul 2012 14:44:03 +0200
From: neurino <lelli.luca@googlemail.com>
Subject: Flushing and multiple pipes
Message-Id: <jubjqj$5mc$1@tdi.cu.mi.it>
Dear group,
happy to post my first message here! So, now the business.
I define two pipes which print both two parsed datastreams on the
_same_ postscript file. The data values are selected through 'commands'
by certain criteria in the following manner:
# shortened pseudocode
#!/usr/bin/perl
my $pipe1 = " commands >> $psfile";
my $pipe2 = " commands >> $psfile";
open(H1 ,"| $pipe1") or die "\n --- Error: Could not plot $pipe1: $!\n";
open(H2 ,"| $pipe2") or die "\n --- Error: Could not plot $pipe2: $!\n";
foreach my $ifile (@ifiles){
open(IFILE, "<$ifile");
while(<IFILE>){
$line = split(/\s+/,$_);
print H1 $line;
print H2 $line;
}
close(IFILE);
}
close(H1);
close(H2);
# end shortened pseudocode
I noticed that, depending on the datastream type, sometimes the
postscript is written and closed correctly, sometimes it does not. I
noticed also that on Ubuntu the script behaves differently than on
Leopard OSX. No fancy modules are loaded, just pure Perl. The
'commands' are a pipe of awk and gmt routines.
To be on the safe side, i duplicated the foreach loop, and now i open
one pipe at a time, guessing that the problem is how the OS flushes the
pipes' buffers and how the postscript file gets the values.
It ain't by any means the best solution, because i have to parse the
same files twice. Then the question: is there a way to open concurrent
pipes in a robust way?
Thanks.
------------------------------
Date: Fri, 20 Jul 2012 14:08:14 +0100
From: Rainer Weikusat <rweikusat@mssgmbh.com>
Subject: Re: Flushing and multiple pipes
Message-Id: <87zk6uk2bl.fsf@sapphire.mobileactivedefense.com>
neurino <lelli.luca@googlemail.com> writes:
[...]
> #!/usr/bin/perl
>
> my $pipe1 = " commands >> $psfile";
> my $pipe2 = " commands >> $psfile";
>
> open(H1 ,"| $pipe1") or die "\n --- Error: Could not plot $pipe1: $!\n";
> open(H2 ,"| $pipe2") or die "\n --- Error: Could not plot $pipe2: $!\n";
>
> foreach my $ifile (@ifiles){
> open(IFILE, "<$ifile");
> while(<IFILE>){
> $line = split(/\s+/,$_);
> print H1 $line;
> print H2 $line;
> }
> close(IFILE);
> }
> close(H1);
> close(H2);
> # end shortened pseudocode
>
> I noticed that, depending on the datastream type, sometimes the
> postscript is written and closed correctly, sometimes it does not.
I assume 'correctly' means you get two differently processed lines for
each input line in the output file, in the order they were written in
perl. That's never going to work reliably in this way because not only
perl employs internal output buffering but the commands running as
part of your pipeline do this as well: If they use stdio, their output
will be 'fully buffered' when stdout is not connected to an
interactive device. Also, the processes in both of your pipelines
execute asynchronously with respect to the Perl control process and
the processes in the other pipeline. This means you may get higher
throughput in this way but the downside is that output reordering may
(and usually will) occur.
The simple but relatively inefficient solution to that is to create
two new pipelines for each input line and don't start the second
before the first has terminated (or the third before the second has
terminated and so on). Unless you're repeatedlyv dealing with large
inputs, this is probably good enough, though. If you wan't to process
the input asynchronously and concurrenly, you need to employ a final
'put it back together' filter which reads data from both pipelines
as it becomes available and puts the output back into the proper
order.
------------------------------
Date: Fri, 20 Jul 2012 15:45:57 +0200
From: neurino <lelli.luca@googlemail.com>
Subject: Re: Flushing and multiple pipes
Message-Id: <jubnel$8e7$1@tdi.cu.mi.it>
On 2012-07-20 15:08:14 +0200, Rainer Weikusat said:
> I assume 'correctly' means you get two differently processed lines for
> each input line in the output file, in the order they were written in
> perl.
Exactly.
> That's never going to work reliably in this way because [...]
Thanks for the explanation. So, it seems i was on the right track somehow.
> The simple but relatively inefficient solution to that is to create
> two new pipelines for each input line and don't start the second
> before the first has terminated (or the third before the second has
> terminated and so on).
This is the way i implemented it now. I could read the files at once
but isn't an option as well. And you are pointing out the issue: the
data records are large enough, 1-2 Gb.
> If you wan't to process the input asynchronously and concurrenly, you
> need to employ a final 'put it back together' filter which reads data
> from both pipelines as it becomes available and puts the output back
> into the proper
> order.
It sounds quite new to me. I found on perfaq5 pack/unpack. Is is right?
Thanks.
------------------------------
Date: Thu, 19 Jul 2012 12:34:49 -0700 (PDT)
From: clearguy02@yahoo.com
Subject: Help needed to finding how many users are in a group..
Message-Id: <32bd11af-b721-4ddd-95e3-95e70188dadb@googlegroups.com>
Hi all,
I have this text file with columns (entries seperated by a tab);
++++++++++++++++++++++
Alabama John
Alabama Victor
California Raj
California Jason
California Lucy
Michigan Peter
++++++++++++++++++++++
Now I want to know how many people are in each state.
The output should be as follows (seperated by tabs).
+++++++++++++++++++++
Alabama 2 1.John
2.Victor
California 3 1. Raj
2. Jason
3. Lucy
Michigan 1 1. Peter
++++++++++++++++++++++
I am try the following, but I am confused with the hash processing after splitting each row in to two values. Can some one help me out here?
+++++++++++++++++++++
while (<DATA>)
{
($state, $name) = split (\t, $_);
...
....
}
__DATA__
Alabama John
Alabama Victor
California Raj
California Jason
California Lucy
Michigan Peter
------------------------------
Date: Thu, 19 Jul 2012 20:54:34 +0100
From: Rainer Weikusat <rweikusat@mssgmbh.com>
Subject: Re: Help needed to finding how many users are in a group..
Message-Id: <87zk6vv85h.fsf@sapphire.mobileactivedefense.com>
clearguy02@yahoo.com writes:
> I have this text file with columns (entries seperated by a tab);
>
> ++++++++++++++++++++++
> Alabama John
> Alabama Victor
> California Raj
> California Jason
> California Lucy
> Michigan Peter
> ++++++++++++++++++++++
>
> Now I want to know how many people are in each state.
> The output should be as follows (seperated by tabs).
> +++++++++++++++++++++
> Alabama 2 1.John
> 2.Victor
>
> California 3 1. Raj
> 2. Jason
> 3. Lucy
>
> Michigan 1 1. Peter
> ++++++++++++++++++++++
>
> I am try the following, but I am confused with the hash processing
> after splitting each row in to two values.
Example which mostly does this
------------------
my (%states, $ppl, $n);
while (<DATA>)
{
chomp;
($state, $name) = split (/\t/, $_);
push(@{$states{$state}}, $name);
}
for (sort(keys(%states))) {
$ppl = $states{$_};
print("$_ ".scalar(@$ppl), "\n");
$n = 0;
print(join("\n", map { "\t".++$n." $_"; } @$ppl), "\n");
}
__DATA__
Alabama John
Alabama Victor
California Raj
California Jason
California Lucy
Michigan Peter
------------------------------
Date: Thu, 19 Jul 2012 15:02:56 -0700 (PDT)
From: clearguy02@yahoo.com
Subject: Re: Help needed to finding how many users are in a group..
Message-Id: <d5a038cb-460b-421f-8312-2ec6d20f3d2b@googlegroups.com>
Thanks Rainer..
That works like a charm. How can I number the states as well?
$l = 0;
print("++$l.$_ ".scalar(@$ppl), "\n"); is not working!!
On Thursday, July 19, 2012 12:54:34 PM UTC-7, Rainer Weikusat wrote:
> clearguy02@yahoo.com writes:
> > I have this text file with columns (entries seperated by a tab);
> >
> > ++++++++++++++++++++++
> > Alabama John
> > Alabama Victor
> > California Raj
> > California Jason
> > California Lucy
> > Michigan Peter
> > ++++++++++++++++++++++
> >
> > Now I want to know how many people are in each state.
> > The output should be as follows (seperated by tabs).
> > +++++++++++++++++++++
> > Alabama 2 1.John
> > 2.Victor
> >
> > California 3 1. Raj
> > 2. Jason
> > 3. Lucy
> >
> > Michigan 1 1. Peter
> > ++++++++++++++++++++++
> >
> > I am try the following, but I am confused with the hash processing
> > after splitting each row in to two values.
>
> Example which mostly does this
>
> ------------------
> my (%states, $ppl, $n);
>
> while (<DATA>)
> {
> chomp;
> ($state, $name) = split (/\t/, $_);
> push(@{$states{$state}}, $name);
> }
>
> for (sort(keys(%states))) {
> $ppl = $states{$_};
> print("$_ ".scalar(@$ppl), "\n");
>
> $n = 0;
> print(join("\n", map { "\t".++$n." $_"; } @$ppl), "\n");
> }
>
> __DATA__
> Alabama John
> Alabama Victor
> California Raj
> California Jason
> California Lucy
> Michigan Peter
------------------------------
Date: Thu, 19 Jul 2012 17:09:40 -0700
From: Jürgen Exner <jurgenex@hotmail.com>
Subject: Re: Help needed to finding how many users are in a group..
Message-Id: <cd8h081puu6bhpo292ac1b5tvau4eltute@4ax.com>
clearguy02@yahoo.com wrote:
>Now I want to know how many people are in each state.
>The output should be as follows (seperated by tabs).
Does this smell like homework to anyone else, too?
jue
------------------------------
Date: Thu, 19 Jul 2012 18:00:53 -0700
From: Jim Gibson <jimsgibson@gmail.com>
Subject: Re: Help needed to finding how many users are in a group..
Message-Id: <190720121800533998%jimsgibson@gmail.com>
In article <d5a038cb-460b-421f-8312-2ec6d20f3d2b@googlegroups.com>,
<clearguy02@yahoo.com> wrote:
> Thanks Rainer..
>
> That works like a charm. How can I number the states as well?
>
> $l = 0;
> print("++$l.$_ ".scalar(@$ppl), "\n"); is not working!!
You have to remove ++$l from its double-quoted context and make it an
expression:
print( ++$l . ".$_ ".scalar(@$ppl), "\n");
--
Jim Gibson
------------------------------
Date: Fri, 20 Jul 2012 13:18:08 +0100
From: Rainer Weikusat <rweikusat@mssgmbh.com>
Subject: Re: Help needed to finding how many users are in a group..
Message-Id: <87629isk1r.fsf@sapphire.mobileactivedefense.com>
Jürgen Exner <jurgenex@hotmail.com> writes:
> clearguy02@yahoo.com wrote:
>>Now I want to know how many people are in each state.
>>The output should be as follows (seperated by tabs).
>
> Does this smell like homework to anyone else, too?
Maybe it does. But it is IMHO much better to show people how to solve
simple problems like that than to force them to rediscover all
well-known solutions which have piled up since the times of Aristotle.
Geniuses are rare and surreptitious(!) for day-to-day
operations. Trained craftsmen are useful.
------------------------------
Date: Thu, 19 Jul 2012 10:43:43 -0400
From: Shmuel (Seymour J.) Metz <spamtrap@library.lspace.org.invalid>
Subject: Re: LibXML element->toString vs document->toString
Message-Id: <50081d1f$2$fuzhry+tra$mr2ice@news.patriot.net>
In <1knd7af.1e602xit3x7eN%fergus@twig-me-uk.not.here>, on 07/17/2012
at 07:21 AM, fergus@twig-me-uk.not.here (Fergus McMenemie) said:
>My newsreader does not properly upport UTF8 I guess lots of others
>still dont either.
Mine doesn't either[1], but that's an issue with my news client, not
with the Usenet standards.
[1] But at least it supports the ISO-8859-* character sets.
--
Shmuel (Seymour J.) Metz, SysProg and JOAT <http://patriot.net/~shmuel>
Unsolicited bulk E-mail subject to legal action. I reserve the
right to publicly post or ridicule any abusive E-mail. Reply to
domain Patriot dot net user shmuel+news to contact me. Do not
reply to spamtrap@library.lspace.org
------------------------------
Date: Thu, 19 Jul 2012 10:49:05 -0400
From: Shmuel (Seymour J.) Metz <spamtrap@library.lspace.org.invalid>
Subject: Re: Regex: match double OR single quote
Message-Id: <50081e61$3$fuzhry+tra$mr2ice@news.patriot.net>
In <877gu1ntli.fsf@sapphire.mobileactivedefense.com>, on 07/18/2012
at 01:26 PM, Rainer Weikusat <rweikusat@mssgmbh.com> said:
>I don't think so.
Because you didn't read Ben's text.
>? is equivalent to the quantifier {0,1}, * is
>equivalent to the quantifier {0,}.
Which doesn't conflict with what Ben wrote.
--
Shmuel (Seymour J.) Metz, SysProg and JOAT <http://patriot.net/~shmuel>
Unsolicited bulk E-mail subject to legal action. I reserve the
right to publicly post or ridicule any abusive E-mail. Reply to
domain Patriot dot net user shmuel+news to contact me. Do not
reply to spamtrap@library.lspace.org
------------------------------
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Subject: Digest Administrivia (Last modified: 6 Apr 01)
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------------------------------
End of Perl-Users Digest V11 Issue 3739
***************************************
