[29491] in Perl-Users-Digest
Perl-Users Digest, Issue: 735 Volume: 11
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Thu Aug 9 16:09:43 2007
Date: Thu, 9 Aug 2007 13:09:12 -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 Thu, 9 Aug 2007 Volume: 11 Number: 735
Today's topics:
checking for newly added files <mislam@npspam.uiuc.edu>
Re: checking for newly added files <larry.grant.dc@gmail.com>
Re: checking for newly added files <larry.grant.dc@gmail.com>
Re: checking for newly added files <m@rtij.nl.invlalid>
Re: checking for newly added files <mislam@npspam.uiuc.edu>
Re: FAQ 7.26 How can I comment out a large block of per <larry.grant.dc@gmail.com>
Re: How to get values and ref types from caller package <el.dodgero@gmail.com>
Re: how to tranpose a huge text file <jiehuang001@gmail.com>
Re: more elegant way to say ($1, $2, $3, $4, ...)? <nobull67@gmail.com>
Re: more elegant way to say ($1, $2, $3, $4, ...)? <larry.grant.dc@gmail.com>
Re: more elegant way to say ($1, $2, $3, $4, ...)? <uri@stemsystems.com>
Re: more elegant way to say ($1, $2, $3, $4, ...)? <uri@stemsystems.com>
more inelegancies <larry.grant.dc@gmail.com>
Re: more inelegancies <mritty@gmail.com>
Re: more inelegancies <larry.grant.dc@gmail.com>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Thu, 09 Aug 2007 14:10:48 -0500
From: Sharif Islam <mislam@npspam.uiuc.edu>
Subject: checking for newly added files
Message-Id: <f9forq$ud3$1@news.ks.uiuc.edu>
I am copying (using scp -p) some text files from another machine and
processing them. I am not sure how to check when a new file
has been added to that particular directory. I will run the perl script
every night and I want it to look for new files, if a new file is there
I want to process it, otherwise ignore it.
#!/usr/bin/perl
use strict;
my $file;
# these are all the copied files
my @files = <*.txt>;
foreach $file (@files) {
my @tm = localtime((stat $file)[9]);
my $filedate=sprintf("%04d-%02d-%02d
%02d:%02d:%02d",$tm[5]+1900,$tm[4]+1,$tm[3],$tm[2],$tm[1],$tm[0]);
print "$filedate\n";
#here i will process the files.
}
------------------------------
Date: Thu, 09 Aug 2007 19:12:36 -0000
From: Larry <larry.grant.dc@gmail.com>
Subject: Re: checking for newly added files
Message-Id: <1186686756.170988.98480@m37g2000prh.googlegroups.com>
On Aug 9, 3:10 pm, Sharif Islam <mis...@npspam.uiuc.edu> wrote:
> I am copying (using scp -p) some text files from another machine and
> processing them. I am not sure how to check when a new file
> has been added to that particular directory. I will run the perl script
> every night and I want it to look for new files, if a new file is there
> I want to process it, otherwise ignore it.
>
> #!/usr/bin/perl
>
> use strict;
> my $file;
> # these are all the copied files
> my @files = <*.txt>;
>
> foreach $file (@files) {
> my @tm = localtime((stat $file)[9]);
> my $filedate=sprintf("%04d-%02d-%02d
> %02d:%02d:%02d",$tm[5]+1900,$tm[4]+1,$tm[3],$tm[2],$tm[1],$tm[0]);
> print "$filedate\n";
> #here i will process the files.
>
> }
Here's where Windows would come in handy :)
You could use the "archive" bit to keep track. I don't know if *nix
has anything similar.
------------------------------
Date: Thu, 09 Aug 2007 19:14:48 -0000
From: Larry <larry.grant.dc@gmail.com>
Subject: Re: checking for newly added files
Message-Id: <1186686888.278414.103290@m37g2000prh.googlegroups.com>
On Aug 9, 3:12 pm, Larry <larry.grant...@gmail.com> wrote:
> On Aug 9, 3:10 pm, Sharif Islam <mis...@npspam.uiuc.edu> wrote:
>
>
>
> > I am copying (using scp -p) some text files from another machine and
> > processing them. I am not sure how to check when a new file
> > has been added to that particular directory. I will run the perl script
> > every night and I want it to look for new files, if a new file is there
> > I want to process it, otherwise ignore it.
>
> > #!/usr/bin/perl
>
> > use strict;
> > my $file;
> > # these are all the copied files
> > my @files = <*.txt>;
>
> > foreach $file (@files) {
> > my @tm = localtime((stat $file)[9]);
> > my $filedate=sprintf("%04d-%02d-%02d
> > %02d:%02d:%02d",$tm[5]+1900,$tm[4]+1,$tm[3],$tm[2],$tm[1],$tm[0]);
> > print "$filedate\n";
> > #here i will process the files.
>
> > }
>
> Here's where Windows would come in handy :)
>
> You could use the "archive" bit to keep track. I don't know if *nix
> has anything similar.
Otherwise, after processing, write a file with the timestamp of the
most recent file that has been processed. Before processing, check
that file, and skip any file with a timestamp <= to that.
------------------------------
Date: Thu, 9 Aug 2007 21:41:13 +0200
From: Martijn Lievaart <m@rtij.nl.invlalid>
Subject: Re: checking for newly added files
Message-Id: <pan.2007.08.09.19.41.13@rtij.nl.invlalid>
On Thu, 09 Aug 2007 14:10:48 -0500, Sharif Islam wrote:
> I am copying (using scp -p) some text files from another machine and
> processing them. I am not sure how to check when a new file has been
> added to that particular directory. I will run the perl script every
> night and I want it to look for new files, if a new file is there I want
> to process it, otherwise ignore it.
If you are on un*x (or Windows with Cygwin) use rsync.
M4
------------------------------
Date: Thu, 09 Aug 2007 14:45:45 -0500
From: Sharif Islam <mislam@npspam.uiuc.edu>
Subject: Re: checking for newly added files
Message-Id: <f9fqt9$v9b$1@news.ks.uiuc.edu>
Martijn Lievaart wrote:
> On Thu, 09 Aug 2007 14:10:48 -0500, Sharif Islam wrote:
>
>> I am copying (using scp -p) some text files from another machine and
>> processing them. I am not sure how to check when a new file has been
>> added to that particular directory. I will run the perl script every
>> night and I want it to look for new files, if a new file is there I want
>> to process it, otherwise ignore it.
>
> If you are on un*x (or Windows with Cygwin) use rsync.
>
> M4
aha! yes, forgot about rsync. Thanks.
--sharif
------------------------------
Date: Thu, 09 Aug 2007 18:11:39 -0000
From: Larry <larry.grant.dc@gmail.com>
Subject: Re: FAQ 7.26 How can I comment out a large block of perl code?
Message-Id: <1186683099.830439.296440@57g2000hsv.googlegroups.com>
On Aug 7, 3:03 pm, PerlFAQ Server <br...@stonehenge.com> wrote:
> 7.26: How can I comment out a large block of perl code?
>
> You can use embedded POD to discard it. Enclose the blocks you want to
> comment out in POD markers. The <=begin> directive marks a section for a
> specific formatter. Use the "comment" format, which no formatter should
> claim to understand (by policy). Mark the end of the block with <=end>.
>
> # program is here
>
> =begin comment
>
> all of this stuff
>
> here will be ignored
> by everyone
>
> =end comment
>
> =cut
>
> # program continues
>
> The pod directives cannot go just anywhere. You must put a pod directive
> where the parser is expecting a new statement, not just in the middle of
> an expression or some other arbitrary grammar production.
>
> See perlpod for more details.
Or... if you are not really using POD in your script, you can do the
easier:
# program is here
=pod
all of this stuff
here will be ignored
by everyone
=cut
# program continues
------------------------------
Date: Thu, 09 Aug 2007 18:17:34 -0000
From: Dodger <el.dodgero@gmail.com>
Subject: Re: How to get values and ref types from caller package
Message-Id: <1186683454.842575.293800@q3g2000prf.googlegroups.com>
On Aug 7, 6:37 pm, mer...@stonehenge.com (Randal L. Schwartz) wrote:
> >>>>> "Dodger" == Dodger <el.dodg...@gmail.com> writes:
>
> Dodger> One of the other problems is that some of the coders have decided to
> Dodger> go ahead and call this thing numberous times even when they don't need
> Dodger> to. Rather than try and hunt down every instance of someone calling
> Dodger> for Foo when they already have a Foo object, i wanted to be able to
> Dodger> look into the symbol table for the caller, find all the variables
> Dodger> there, and check to see if any of the scalars are, in fact, already a
> Dodger> Foo, and, if so, just to return that and do nothing else. This would
> Dodger> bypass the need to check to make sure it's the right *kind* of Foo
> Dodger> because the first time a Foo was grabbed it would be and the
> Dodger> environment doesn't change at runtime. It's safe to trust the former
> Dodger> Foo is the right kind of Foo.
>
> That seems like the hard way. Why don't you just cache the result from
> Foo->new, using some sort of aspect programming (replace ->new with something
> that watches the inputs and return values from the real ->new)?
>
> --
> Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
> <mer...@stonehenge.com> <URL:http://www.stonehenge.com/merlyn/>
> Perl/Unix/security consulting, Technical writing, Comedy, etc. etc.
> See PerlTraining.Stonehenge.com for onsite and open-enrollment Perl training!
>
> --
> Posted via a free Usenet account fromhttp://www.teranews.com
Out of curiosity, though... even if this isn't the right way to go,
how can I do this if some time it is the right (or only) solution? Is
there a way to peek right into and get the variables out of the
calling package, maybe even manipulate them?
--
Dodger
------------------------------
Date: Thu, 09 Aug 2007 19:32:33 -0000
From: Jie <jiehuang001@gmail.com>
Subject: Re: how to tranpose a huge text file
Message-Id: <1186687953.005301.137240@e16g2000pri.googlegroups.com>
Hi, Thank you so much for all the responses.
First, here is a sample dataset, but the real one is much bigger, with
1,000 columns instead of 14.
http://www.humanbee.com/BIG.txt
I could think of two ways to transpose this file.
Option1: write a line as a column and append, something like below
open IN, "<big_file.txt";
open OUT, ">transposed_file.txt";
while (IN) {
append ??????????????
}
Option 2: generate a huge 2-dimentional array and write it out in the
other way
$row=0;
while (IN) {
$big_ARRAY[$row][] = split(/ /);
}
foreach $row (0 ..$row) {
foreach $column (0 ..$#big_ARRAY) {
print OUT$big_ARRAY[$column][$row];
}
}
But I really doubt that either will work. So, can someone please throw
some idea and hopefully code here?!
Thank you!!
Jie
------------------------------
Date: Thu, 09 Aug 2007 18:29:13 -0000
From: Brian McCauley <nobull67@gmail.com>
Subject: Re: more elegant way to say ($1, $2, $3, $4, ...)?
Message-Id: <1186684153.441836.4630@57g2000hsv.googlegroups.com>
On Aug 9, 7:04 pm, Larry <larry.grant...@gmail.com> wrote:
> I'm using a /g regex in a while loop to capture parenthesized matches
> to meaningful variable names like this:
>
> while (/ (...) ... (...) ... (...)/g) {
> my ($foo, $bar, $baz) = ($1, $2, $3);
> ...
>
> }
>
> The ($1, $2, $3) part seems inelegant ... is there a more elegant way?
Not that I know of in Perl5 - and believe me I've looked.
You could write a function that returns them
sub matches { no strict 'refs'; map $$_ , 1 .. $#- }
while (/ (...) ... (...) ... (...)/g) {
my ($foo, $bar, $baz) = matches;
}
But this is hardly more elegant.
------------------------------
Date: Thu, 09 Aug 2007 18:52:55 -0000
From: Larry <larry.grant.dc@gmail.com>
Subject: Re: more elegant way to say ($1, $2, $3, $4, ...)?
Message-Id: <1186685575.597569.49770@e16g2000pri.googlegroups.com>
On Aug 9, 2:29 pm, Brian McCauley <nobul...@gmail.com> wrote:
> On Aug 9, 7:04 pm, Larry <larry.grant...@gmail.com> wrote:
>
> > I'm using a /g regex in a while loop to capture parenthesized matches
> > to meaningful variable names like this:
>
> > while (/ (...) ... (...) ... (...)/g) {
> > my ($foo, $bar, $baz) = ($1, $2, $3);
> > ...
>
> > }
>
> > The ($1, $2, $3) part seems inelegant ... is there a more elegant way?
>
> Not that I know of in Perl5 - and believe me I've looked.
>
> You could write a function that returns them
>
> sub matches { no strict 'refs'; map $$_ , 1 .. $#- }
>
> while (/ (...) ... (...) ... (...)/g) {
> my ($foo, $bar, $baz) = matches;
>
> }
>
> But this is hardly more elegant.
Not elegant?! It's awesome! Thanks!
BTW, I just learned 2 new things:
-- map can take an expr as the first param, not just a block (had to
look that up to see what was going on exactly!)
-- that there is a variable called @- and what it does
Thanks!
------------------------------
Date: Thu, 09 Aug 2007 19:08:14 GMT
From: Uri Guttman <uri@stemsystems.com>
Subject: Re: more elegant way to say ($1, $2, $3, $4, ...)?
Message-Id: <x7d4xwle5a.fsf@mail.sysarch.com>
>>>>> "L" == Larry <larry.grant.dc@gmail.com> writes:
L> I'm using a /g regex in a while loop to capture parenthesized matches
L> to meaningful variable names like this:
L> while (/ (...) ... (...) ... (...)/g) {
L> my ($foo, $bar, $baz) = ($1, $2, $3);
L> ...
L> }
L> The ($1, $2, $3) part seems inelegant ... is there a more elegant way?
you can look at using @+, @- to get the strings via substr. a map call
on 0 .. $#+ will do it but it is ugly too
perldoc perlvar says this:
$1 is the same as "substr($var, $-[1], $+[1] - $-[1])"
so this should work (untested):
my ($foo, $bar, $baz) =
map substr($var, $-[$_], $+[$_] - $-[$_]), 0 .. $#+ ;
and that map stuff could be put into a sub to clean it up. just pass in
$var and the @+ and @- globals should still be set. something like this:
sub matches {
map substr($_[0], $-[$_], $+[$_] - $-[$_]), 0 .. $#+ ;
}
my ($foo, $bar, $baz) = matches( $var ) ;
but i would just stick with the assignment of $1, $2 ... as it is the
cleanest.
uri
--
Uri Guttman ------ uri@stemsystems.com -------- http://www.stemsystems.com
--Perl Consulting, Stem Development, Systems Architecture, Design and Coding-
Search or Offer Perl Jobs ---------------------------- http://jobs.perl.org
------------------------------
Date: Thu, 09 Aug 2007 19:10:17 GMT
From: Uri Guttman <uri@stemsystems.com>
Subject: Re: more elegant way to say ($1, $2, $3, $4, ...)?
Message-Id: <x78x8kle1v.fsf@mail.sysarch.com>
>>>>> "L" == Larry <larry.grant.dc@gmail.com> writes:
L> On Aug 9, 2:29 pm, Brian McCauley <nobul...@gmail.com> wrote:
>> On Aug 9, 7:04 pm, Larry <larry.grant...@gmail.com> wrote:
>> You could write a function that returns them
>>
>> sub matches { no strict 'refs'; map $$_ , 1 .. $#- }
>>
>> while (/ (...) ... (...) ... (...)/g) {
>> my ($foo, $bar, $baz) = matches;
>>
>> }
>>
>> But this is hardly more elegant.
L> Not elegant?! It's awesome! Thanks!
it is not elegant as it uses symrefs which is evil. see my other post
for a solution without symrefs.
L> -- that there is a variable called @- and what it does
and see @+ and how perlvar says to use them. my other post shows a full
example without symrefs.
uri
--
Uri Guttman ------ uri@stemsystems.com -------- http://www.stemsystems.com
--Perl Consulting, Stem Development, Systems Architecture, Design and Coding-
Search or Offer Perl Jobs ---------------------------- http://jobs.perl.org
------------------------------
Date: Thu, 09 Aug 2007 18:59:36 -0000
From: Larry <larry.grant.dc@gmail.com>
Subject: more inelegancies
Message-Id: <1186685976.680652.162430@g12g2000prg.googlegroups.com>
While we are on the subject of inelegancies ... what if I want to
assign the elements of @zam to scalars, but I don't care about
$zam[2]? I'd like to do:
my ($foo, $bar, undef, $baz) = @zam;
but that won't compile, so I'm forced to do:
my ($foo, $bar, $baz);
($foo, $bar, undef, $baz) = @zam;
Any better way?
And furthermore....
What if $foo and $baz are already my'ed... I'd like to do:
($foo, my $bar, $baz) = @wham;
but Perl doesn't like that either, so I have to do:
my $bar;
($foo, $bar, $baz) = @wham;
------------------------------
Date: Thu, 09 Aug 2007 12:35:54 -0700
From: Paul Lalli <mritty@gmail.com>
Subject: Re: more inelegancies
Message-Id: <1186688154.537550.134860@q3g2000prf.googlegroups.com>
On Aug 9, 2:59 pm, Larry <larry.grant...@gmail.com> wrote:
> While we are on the subject of inelegancies ... what if I want to
> assign the elements of @zam to scalars, but I don't care about
> $zam[2]? I'd like to do:
>
> my ($foo, $bar, undef, $baz) = @zam;
>
> but that won't compile,
Says who?
$ perl -le'
my @zam = qw/alpha beta gamma delta/;
my ($foo, $bar, undef, $baz) = @zam;
print for $foo, $bar, $baz;
'
alpha
beta
delta
> Any better way?
Array slices.
$ perl -le'
my @zam = qw/alpha beta gamma delta/;
my ($foo, $bar, $baz) = @zam[0,1,3];
print for $foo, $bar, $baz;
'
alpha
beta
delta
> And furthermore....
>
> What if $foo and $baz are already my'ed... I'd like to do:
>
> ($foo, my $bar, $baz) = @wham;
>
> but Perl doesn't like that either
Exactly what version of Perl are you running? This, again, works just
fine for me.
$ perl -le'
my @zam = qw/alpha beta gamma delta/;
my ($foo, $baz);
($foo, my $bar, $baz) = @zam[0,1,3];
print for $foo, $bar, $baz;
'
alpha
beta
delta
And indeed, B::Deparse even shows us that it's doing exactly what we
mean (that the second 'my' applies only to $bar, not $baz:
$ perl -MO=Deparse,-p -le'
my @zam = qw/alpha beta gamma delta/;
my ($foo, $baz);
($foo, my $bar, $baz) = @zam[0,1,3];
print for $foo, $bar, $baz;
'
BEGIN { $/ = "\n"; $\ = "\n"; }
(my(@zam) = ('alpha', 'beta', 'gamma', 'delta'));
my($foo, $baz);
(($foo, my($bar), $baz) = @zam[0, 1, 3]);
;
foreach $_ (($foo, $bar, $baz)) {
print($_);
}
-e syntax OK
Paul Lalli
------------------------------
Date: Thu, 09 Aug 2007 19:57:03 -0000
From: Larry <larry.grant.dc@gmail.com>
Subject: Re: more inelegancies
Message-Id: <1186689423.305785.192040@q3g2000prf.googlegroups.com>
On Aug 9, 3:35 pm, Paul Lalli <mri...@gmail.com> wrote:
> Exactly what version of Perl are you running? This, again, works just
> fine for me.
??!!! They are working for me too! I don't know what I was
thinking... maybe they used to not work in some older version of Perl
and I never checked.... ??
------------------------------
Date: 6 Apr 2001 21:33:47 GMT (Last modified)
From: Perl-Users-Request@ruby.oce.orst.edu (Perl-Users-Digest Admin)
Subject: Digest Administrivia (Last modified: 6 Apr 01)
Message-Id: <null>
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------------------------------
End of Perl-Users Digest V11 Issue 735
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