[24463] in Perl-Users-Digest
Perl-Users Digest, Issue: 6646 Volume: 10
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Wed Jun 2 14:11:49 2004
Date: Wed, 2 Jun 2004 11:10:07 -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 Wed, 2 Jun 2004 Volume: 10 Number: 6646
Today's topics:
sorting and resorting hash (Andrea Spitaleri)
Re: sorting and resorting hash <ittyspam@yahoo.com>
Re: sorting and resorting hash <usenet@morrow.me.uk>
Re: sorting and resorting hash <usenet@morrow.me.uk>
Re: sorting and resorting hash <ittyspam@yahoo.com>
Re: sorting and resorting hash <nobull@mail.com>
Re: SSL connection to oracle using DBI? <Juha.Laiho@iki.fi>
Unexpected subroutine behaviour without & (Kevin Collins)
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: 2 Jun 2004 09:02:06 -0700
From: spiritelllo@interfree.it (Andrea Spitaleri)
Subject: sorting and resorting hash
Message-Id: <4de1519a.0406020802.4a977ced@posting.google.com>
Hi,
the below code works great but I would like to receive some comment
about its perl-ish style. (I am not new posting this kind of messagge,
but I want improve my style) :-)
the problem is: I have several file, which they need to be ranked.
i.e.:
1.sft contains rms 1
2.sft contains rms 3
3.sft contains rms 2
4.sft contains rms 0.5
5.sft contains rms 3
.......
and I would like to get at the end symbolic link, ranking the file bye
rms values:
rank_1.sft ---> 4.sft
rank_2.sft ---> 1.sft
rank_3.sft ---> 3.sft
rank_4.sft ---> 2.sft
rank_5.sft ---> 5.sft
........
#!/usr/bin/perl
use warnings;
foreach my $index (1 .. $ARGV[0]){
open (FILE,"<$index.sft") || die "cannot open $index.sft : $!";
while($line=<FILE>) {
chomp $line;
if($line=~/^rms/){
@info=split(/ /,$line);
push @rms,$index,$info[1];
%rms = @rms;
}
}
}
print "@rms\n";
print "file ==> value rms\n";
sub tmp {
$rms{$a}<=>$rms{$b};
}
foreach $key (sort tmp (keys (%rms))){
# print "$rms[$key] --> $key.sft -->> $rms{$key}\n";
print "$key.sft -->> $rms{$key}\n";
push @new,$key;
}
for ($i=1;$i<=$#new+1;++$i){
print "$i\_rank -->> $new[$i-1].sft\n";
system ("ln -s $new[$i-1].sft $i\_rank.sft");
}
# thanks
# regards
# xspirix
------------------------------
Date: Wed, 2 Jun 2004 12:57:35 -0400
From: Paul Lalli <ittyspam@yahoo.com>
Subject: Re: sorting and resorting hash
Message-Id: <20040602123732.Q8971@dishwasher.cs.rpi.edu>
On Wed, 2 Jun 2004, Andrea Spitaleri wrote:
> Hi,
> the below code works great but I would like to receive some comment
> about its perl-ish style. (I am not new posting this kind of messagge,
> but I want improve my style) :-)
> the problem is: I have several file, which they need to be ranked.
> i.e.:
> 1.sft contains rms 1
> 2.sft contains rms 3
> 3.sft contains rms 2
> 4.sft contains rms 0.5
> 5.sft contains rms 3
> .......
> and I would like to get at the end symbolic link, ranking the file bye
> rms values:
> rank_1.sft ---> 4.sft
> rank_2.sft ---> 1.sft
> rank_3.sft ---> 3.sft
> rank_4.sft ---> 2.sft
> rank_5.sft ---> 5.sft
> ........
> #!/usr/bin/perl
>
> use warnings;
> foreach my $index (1 .. $ARGV[0]){
> open (FILE,"<$index.sft") || die "cannot open $index.sft : $!";
> while($line=<FILE>) {
> chomp $line;
> if($line=~/^rms/){
> @info=split(/ /,$line);
> push @rms,$index,$info[1];
> %rms = @rms;
> }
First, you need to clarify something a little. Does each file contain
at most one line that matches "rms"? That seems to be what you're
implying with your code, so it's the assumption I'll make too. I would
replace your whole if statment with this:
if ($line =~ /^rms\s+(.*)/){
$rms{$index} = $1;
}
There's no reason to be adding values to an array if you're only using
that array to build a hash. Just build the hash directly. Plus this will
avoid needlessly creating the temporary @info as well as the reassigning
of the entire %rms hash each time through the loop.
> }
> }
> print "@rms\n";
> print "file ==> value rms\n";
> sub tmp {
> $rms{$a}<=>$rms{$b};
> }
> foreach $key (sort tmp (keys (%rms))){
> # print "$rms[$key] --> $key.sft -->> $rms{$key}\n";
> print "$key.sft -->> $rms{$key}\n";
> push @new,$key;
> }
> for ($i=1;$i<=$#new+1;++$i){
> print "$i\_rank -->> $new[$i-1].sft\n";
> system ("ln -s $new[$i-1].sft $i\_rank.sft");
>
> }
Why are you creating a whole new array to just store the keys of the hash
that already exists, if you're just using that array to loop over the
keys?
[untested]
@sorted = sort tmp keys %rms;
foreach $key (@sorted) {
print "$key.sft --> $rms{$key}\n";
}
my $i = 1;
foreach $key (@sorted){
print "${i}_rank --> $key.sft\n";
system ("ln -s $key.sft ${i}_rank.sft");
$i++;
}
The "${i}" method is the standard way of setting apart the variable name
from anything else in the string, rather than backslashing the following
character.
On another note, the expression $i<=$#new+1 is ugly. Much preferred (if
you want to insist on a C-style loop, rather than a foreach loop - see
another recent thread in this newsgroup) would be $i <= @new
Paul Lalli
------------------------------
Date: Wed, 2 Jun 2004 17:02:19 +0000 (UTC)
From: Ben Morrow <usenet@morrow.me.uk>
Subject: Re: sorting and resorting hash
Message-Id: <c9l16r$pjg$1@wisteria.csv.warwick.ac.uk>
Quoth spiritelllo@interfree.it (Andrea Spitaleri):
> Hi,
> the below code works great but I would like to receive some comment
> about its perl-ish style. (I am not new posting this kind of messagge,
> but I want improve my style) :-)
> the problem is: I have several file, which they need to be ranked.
> i.e.:
> 1.sft contains rms 1
> 2.sft contains rms 3
> 3.sft contains rms 2
> 4.sft contains rms 0.5
> 5.sft contains rms 3
> .......
> and I would like to get at the end symbolic link, ranking the file bye
> rms values:
> rank_1.sft ---> 4.sft
> rank_2.sft ---> 1.sft
> rank_3.sft ---> 3.sft
> rank_4.sft ---> 2.sft
> rank_5.sft ---> 5.sft
> ........
> #!/usr/bin/perl
>
> use warnings;
use strict;
my (@rms, %rms);
> foreach my $index (1 .. $ARGV[0]){
It is perhaps not terribly 'Perlish' to use 'foreach' as 'for' will do.
> open (FILE,"<$index.sft") || die "cannot open $index.sft : $!";
open my $FILE, '<', "$index.sft" or die "...";
This FH will then close at the end of the scope (as written, your code
didn't close the last FH till the end of the script).
> while($line=<FILE>) {
while (<$FILE>) {
> chomp $line;
> if($line=~/^rms/){
chomp;
But there's no need to as you split the line anyway.
if (/^rms/) {
etc.
> @info=split(/ /,$line);
^^ my
> push @rms,$index,$info[1];
> %rms = @rms;
Why are you doing this? Why not just use %rms? Anyway, why do you make
the assignment every time through the loop? Try:
$rms{$index} = (split)[1];
or, since your keys are numeric and contiguous:
push @rms, (split)[1];
> }
> }
> }
> print "@rms\n";
> print "file ==> value rms\n";
$\ = "\n";
print @rms;
print "file ==> value rms";
Or what I'd actually do is add '-l' to the #! line.
> sub tmp {
> $rms{$a}<=>$rms{$b};
> }
> foreach $key (sort tmp (keys (%rms))){
There's no need for a named sub:
for my $key (sort { $rms{$a} <=> $rms{b} } keys %rms) {
> # print "$rms[$key] --> $key.sft -->> $rms{$key}\n";
> print "$key.sft -->> $rms{$key}\n";
> push @new,$key;
> }
> for ($i=1;$i<=$#new+1;++$i){
This is never necessary.
for my $i (0..$#new) {
(obviously you now have $i values one less than before...)
> print "$i\_rank -->> $new[$i-1].sft\n";
> system ("ln -s $new[$i-1].sft $i\_rank.sft");
There's no need to use system: perl has a symlink function.
I think you have your data structure backwards. I would use a hash the
other way round:
#!/usr/bin/perl -l
use warnings;
use strict;
my %rms;
$/ = undef;
for my $sft (1..$ARGV[0]) {
$sft .= '.sft';
open my $FILE, '<', $sft or die "can't open $sft: $!";
<$FILE> =~ /^rms (\S+)/m and $rms{$1} = $sft;
}
my $i;
for (sort keys %rms) {
my $sym = ++$i . '_rank.sft';
print "create symlink $sym -> $rms{$_} (rms: $_)";
symlink $rms{$_}, $sym or die "symlink failed: $!";
}
__END__
Ben
--
"If a book is worth reading when you are six, * ben@morrow.me.uk
it is worth reading when you are sixty." - C.S.Lewis
------------------------------
Date: Wed, 2 Jun 2004 17:07:07 +0000 (UTC)
From: Ben Morrow <usenet@morrow.me.uk>
Subject: Re: sorting and resorting hash
Message-Id: <c9l1fr$pjg$2@wisteria.csv.warwick.ac.uk>
Quoth Paul Lalli <ittyspam@yahoo.com>:
> On another note, the expression $i<=$#new+1 is ugly. Much preferred (if
> you want to insist on a C-style loop, rather than a foreach loop - see
> another recent thread in this newsgroup) would be $i <= @new
I have to disagree here :). $#new is an ordinal, @new is a cardinal:
comparing an index to @new isn't right. A *much* better solution is, if
you're going to iterate over ordinals, iterate over ordinals:
for my $i (0..$#new) {
(or, for the pedantic,
for my $i ($[ .. $#new) {
:)
Ben
--
"The Earth is degenerating these days. Bribery and corruption abound.
Children no longer mind their parents, every man wants to write a book,
and it is evident that the end of the world is fast approaching."
-Assyrian stone tablet, c.2800 BC ben@morrow.me.uk
------------------------------
Date: Wed, 2 Jun 2004 13:13:11 -0400
From: Paul Lalli <ittyspam@yahoo.com>
Subject: Re: sorting and resorting hash
Message-Id: <20040602131048.J8971@dishwasher.cs.rpi.edu>
On Wed, 2 Jun 2004, Ben Morrow wrote:
> Quoth Paul Lalli <ittyspam@yahoo.com>:
> > On another note, the expression $i<=$#new+1 is ugly. Much preferred (if
> > you want to insist on a C-style loop, rather than a foreach loop - see
> > another recent thread in this newsgroup) would be $i <= @new
>
> I have to disagree here :). $#new is an ordinal, @new is a cardinal:
> comparing an index to @new isn't right. A *much* better solution is, if
> you're going to iterate over ordinals, iterate over ordinals:
>
> for my $i (0..$#new) {
>
> (or, for the pedantic,
>
> for my $i ($[ .. $#new) {
TMTOWTDI, of course. I just can't see typing $#new+1 when @new does just
as well, and is (at least to me) just as readable, if not more.
Now, on the other hand, had the OP actually had a foreach-style loop,
starting at 0, as you suggested, I surely would have recommended $#new as
opposed to @new-1.
Paul Lalli
------------------------------
Date: 02 Jun 2004 18:22:01 +0100
From: Brian McCauley <nobull@mail.com>
Subject: Re: sorting and resorting hash
Message-Id: <u9hdttg9ja.fsf@wcl-l.bham.ac.uk>
spiritelllo@interfree.it (Andrea Spitaleri) writes:
> the below code works great but I would like to receive some comment
> about its perl-ish style. (I am not new posting this kind of messagge,
> but I want improve my style) :-)
> #!/usr/bin/perl
use strict;
Putting this in your code will help you to find all the places you've
forgotten to put my.
> use warnings;
> foreach my $index (1 .. $ARGV[0]){
> open (FILE,"<$index.sft") || die "cannot open $index.sft : $!";
> while($line=<FILE>) {
^^
Missing my.
> chomp $line;
> if($line=~/^rms/){
> @info=split(/ /,$line);
^^
Missing my.
Why use an array if you only want one value?
> push @rms,$index,$info[1];
> %rms = @rms;
Why does @rms exist?
Why not just say:
$rms{$index} = $info[1];
> }
> }
> }
> print "@rms\n";
> print "file ==> value rms\n";
> sub tmp {
> $rms{$a}<=>$rms{$b};
> }
tmp is a bad name for a subroutine.
Actually there's no need to make this subroutine at all.
> foreach $key (sort tmp (keys (%rms))){
^^
Missing my.
> # print "$rms[$key] --> $key.sft -->> $rms{$key}\n";
> print "$key.sft -->> $rms{$key}\n";
> push @new,$key;
> }
Why not just:
my @new = sort { $rms{$a}<=>$rms{$b} } keys (%rms);
but as I said abouve you shouldn't use a hash at all.
> for ($i=1;$i<=$#new+1;++$i){
^^
Missing my.
More conventionally written.
for my $i ( 1 .. @new ) {
> print "$i\_rank -->> $new[$i-1].sft\n";
> system ("ln -s $new[$i-1].sft $i\_rank.sft");
> }
Use the builtin symlink() function rather than running an external
process.
All in all I think it can be a lot simpler:
#!/usr/bin/perl
use strict;
use warnings;
my %rms;
foreach my $index (1 .. $ARGV[0]){
open (FILE,"<$index.sft") or die "cannot open $index.sft : $!";
while(my $line = <FILE>) {
$rms{$index} = $1 if $line =~ /^rms (.*)/;
}
}
my $rank;
for my $index ( sort { $rms{$a} <=> $rms{$b} } keys %rms ){
$rank++;
print "$rank\_rank -->> $index.sft\n";
symlink("$index.sft","$rank\_rank.sft") or warn $!;
}
--
\\ ( )
. _\\__[oo
.__/ \\ /\@
. l___\\
# ll l\\
###LL LL\\
------------------------------
Date: Wed, 02 Jun 2004 16:17:03 GMT
From: Juha Laiho <Juha.Laiho@iki.fi>
Subject: Re: SSL connection to oracle using DBI?
Message-Id: <c9ku8u$6fq$1@ichaos.ichaos-int>
Joe User <william.bathurst@nospam.com> said:
>Has anyone done this before? If so, please let me know. Just
>remove the "nospam" and put in oracle in my email. Or, just reply
>to my post.
Note that if you're using Oracle MTS (multithreaded server)
functionality, this'll become difficult (I'm not certain if
impossible, but difficult at least). Without MTS (so, with
traditional dedicated-server setup) this might be doable with
stunnel, as described in another response.
--
Wolf a.k.a. Juha Laiho Espoo, Finland
(GC 3.0) GIT d- s+: a C++ ULSH++++$ P++@ L+++ E- W+$@ N++ !K w !O !M V
PS(+) PE Y+ PGP(+) t- 5 !X R !tv b+ !DI D G e+ h---- r+++ y++++
"...cancel my subscription to the resurrection!" (Jim Morrison)
------------------------------
Date: Wed, 02 Jun 2004 17:20:42 GMT
From: spamtotrash@toomuchfiction.com (Kevin Collins)
Subject: Unexpected subroutine behaviour without &
Message-Id: <slrncbs335.93b.spamtotrash@doom.unix-guy.com>
Hi,
I've just stumbled across a strange problem on my HP-UX systems. The
following code will demonstrate the problem:
#!/usr/bin/perl -w
use strict;
use warnings;
my @list = qw(cc aa bb aa dd zz ee);
print join(" ", sort(UniqArray(@list))) . "\n";
print join(" ", sort(&UniqArray(@list))) . "\n";
sub UniqArray
{
# This function takes an array reference and returns
# an array without dups
# local variables
my %tmp;
my @returns;
foreach (@list)
{
# if the hash element has a value, then don't
# add it to return list since we've already added it
push (@returns, $_) unless ($tmp{$_});
$tmp{$_}++;
}
return @returns;
}
I have two different "home built" versions of Perl (5.6.1 and 5.8.0) and two
HP-supplied versions (5.6.1 and 5.8.0).
The output I would expect:
aa bb cc dd ee zz
aa bb cc dd ee zz
However, here is what I see:
Custom 5.6.1:
ee zz dd aa bb aa cc
aa bb cc dd ee zz
Custom 5.8.0:
ee zz dd aa bb aa cc
aa bb cc dd ee zz
HP's 5.6.1:
ee zz dd aa bb aa cc
aa bb cc dd ee zz
HP's 5.8.0:
aa bb cc dd ee zz
aa bb cc dd ee zz
I also checked Perl 5.8.0 on RedHat 9.0 and see my expected results. I'm
wondering why I need to call &UniqArray(@list) instead of UniqArray(@list)? I
started looking into this when a new script was not giving me a correctly
sorted list. Is there some know issue with this?
Thanks,
Kevin
------------------------------
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 V10 Issue 6646
***************************************
