[23983] in Perl-Users-Digest
Perl-Users Digest, Issue: 6184 Volume: 10
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Tue Feb 24 03:05:34 2004
Date: Tue, 24 Feb 2004 00:05:04 -0800 (PST)
From: Perl-Users Digest <Perl-Users-Request@ruby.OCE.ORST.EDU>
To: Perl-Users@ruby.OCE.ORST.EDU (Perl-Users Digest)
Perl-Users Digest Tue, 24 Feb 2004 Volume: 10 Number: 6184
Today's topics:
Re: finding common words <dwall@fastmail.fm>
Re: finding common words <dwall@fastmail.fm>
Re: help on hash of hashes (Anno Siegel)
Re: how to use the pm in other location instead of curr (Anno Siegel)
Re: parsing data file into mysql table - help <gpatnude@adelphia.net>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Mon, 23 Feb 2004 14:34:43 -0000
From: "David K. Wall" <dwall@fastmail.fm>
Subject: Re: finding common words
Message-Id: <Xns94986170C204Adkwwashere@216.168.3.30>
Tore Aursand <tore@aursand.no> wrote:
> my %ListA = ( apple => 1.1, banana => 2.2, cat => 3.3 );
> my %ListB = ( apple => 100, boy => 500, cat => 1000 );
> my @common = grep { $ListB{$_} } keys %ListA;
> for ( sort @common ) {
> print "$_\t$ListA{$_}\t$_\t$ListB{$_}\n";
> }
>
> Anything wrong with this one?
One nitpick: make it
my @common = grep { exists $ListB{$_} } keys %ListA;
in case %listB has a key whose value is false.
It's interesting to see so many different ways to do it. :-)
--
David Wall
------------------------------
Date: Mon, 23 Feb 2004 14:40:29 -0000
From: "David K. Wall" <dwall@fastmail.fm>
Subject: Re: finding common words
Message-Id: <Xns9498626A7B8E7dkwwashere@216.168.3.30>
David K. Wall <dwall@fastmail.fm> wrote:
> Tore Aursand <tore@aursand.no> wrote:
>
>> my %ListA = ( apple => 1.1, banana => 2.2, cat => 3.3 );
>> my %ListB = ( apple => 100, boy => 500, cat => 1000 );
>> my @common = grep { $ListB{$_} } keys %ListA;
>> for ( sort @common ) {
>> print "$_\t$ListA{$_}\t$_\t$ListB{$_}\n";
>> }
>>
>> Anything wrong with this one?
>
> One nitpick: make it
>
> my @common = grep { exists $ListB{$_} } keys %ListA;
>
> in case %listB has a key whose value is false.
Oh, I see you already did that in another part of your post. Never mind.
I like it better than my adaptation of the 'intersection' FAQ answer.
--
David Wall
------------------------------
Date: 23 Feb 2004 15:13:22 GMT
From: anno4000@lublin.zrz.tu-berlin.de (Anno Siegel)
Subject: Re: help on hash of hashes
Message-Id: <c1d5ai$878$1@mamenchi.zrz.TU-Berlin.DE>
Stephen Moon <vibfft@yahoo.com> wrote in comp.lang.perl.misc:
> Anno,
[...]
> > > sub transpose {
> > > my $max = 0;
> > > $max > @$_ or $max = @$_ for @_; # length of longest line
> > > map [ map shift( @$_) || '', @_], 1 .. $max;
> > > }
>
> I have a hard time figuring out how transpose function. Maybe, a
> little explanation? Especially where you have "map [ map shift( @$_)
> || '',@_], 1 .. $max"
Well, it is rather compressed, so let's make it more explicit. First let's
expand the outer map and introduce meaningful variable names and some
comments along the way. (I'll assume $max has been calculated as before.
Since it's the length of the longest line it is also the number of lines
in the transposed matrix).
my @lines = @_; # an array of arrays which represents a matrix
my @cols; # will become the transposed matrix
# extract $max columns
for ( 1 .. $max ) {
push @cols, [ map shift @$_ || '', @lines]; # unchanged
}
# done, return result
@cols;
Now do the same with the inner map. We are using a fundamental identity
here. If some expression EXPR returns a list there are two ways to
get an array reference to that list. You can write
$ref = [ EXPR ];
or you can do
my @array = LIST;
$ref = \ @array;
The original code uses the first way for each (anonymous) column. The
expanded code uses the second with the named variable @col. The result
is the same.
my @lines = @_; # an array of arrays which represents a matrix
my @cols; # will become the transposed matrix
# extract $max columns
for ( 1 .. $max ) {
# extract one column
my @col;
# walk through all lines
for my $line ( @lines ) {
# shave off one element of $line and add it to the current
# column. if there are no more elements left in the line, add
# an empty string. $line is destroyed in the process.
push @col, shift @$line || '';
}
# another column is ready, push it onto the result list
push @cols, \ @col;
}
# done, return result
@cols;
I hope that makes things clearer.
As presented, this transposition routine isn't quite a general-purpose
matrix transposition. For one, it's destructive. After using it on
a matrix, the matrix lines will be reduced to empty lists. A general-
purpose routine shouldn't do that. At least, a property like that must
be documented. In blinking red, with a howling background noise.
Secondly, it replaces undefined elements in the original matrix with
empty strings. (Sloppily, it would even replace a 0 element with an
empty string.) A general purpose routine has no business doing that,
but in the case at hand it was convenient.
> Furthermore, what would be difference in using
> {} instead of [].
"{}" produces a hashref from a list of pairs. "[]" produces an
arrayref from any list. The two are never[1] interchangeable.
Anno.
[1] Huh. I said "never" about a Perl construct. Someone is going to
come up with a counter-example.
------------------------------
Date: 23 Feb 2004 15:34:59 GMT
From: anno4000@lublin.zrz.tu-berlin.de (Anno Siegel)
Subject: Re: how to use the pm in other location instead of current one.
Message-Id: <c1d6j3$878$2@mamenchi.zrz.TU-Berlin.DE>
Franklin Lee <pengtaoli@hotmail.com> wrote in comp.lang.perl.misc:
> Hi All,
>
> Now I have some pl and pm files in /opt/myapp/bin.
> But some pm (the same name with previous) may exit dir /opt/myapp/newbin.
> If this dir exist, I want to use the pm in it.
>
> So I write below codes:
> /opt/myapp/bin/app.pl
> **********************************************
> BEGIN {
> if(-r /opt/myapp/newbin) {
Missing quotes. This would result in a syntax error. Please copy/paste
code, don't re-type it.
> unshift(@INC, "/opt/myapp/newbin");
> } else {
> unshift(@INC, "/opt/myapp/bin");
> }
> }
>
> #my code begin....
> require "mymodule.pm";
>
> use strict;
> ....
> ***************************************************
>
> It seems work. The program load the PM in /opt/myapp/newbin/mymodule.pm.
> But I don't see this kind of example some where.
>
> So I want to know if it is a good one orthere exist better solution?
You can "use lib" instead, which saves you the BEGIN block:
use lib -r '/opt/myapp/newbin' ? '/opt/myapp/newbin' : '/opt/myapp/bin';
The expression after "lib" is evaluated at compile time, it piggybacks on
the compile-time execution of "use", as it were.
Anno
------------------------------
Date: Mon, 23 Feb 2004 07:25:02 -0800
From: "Greg Patnude" <gpatnude@adelphia.net>
Subject: Re: parsing data file into mysql table - help
Message-Id: <YIadneURiPzohqfdRVn-sQ@adelphia.com>
You've got AutoCommit set to off when you connect -- your database wont see
the inserted data until after you issue a $dbh->Commit();
--
Greg Patnude / The Digital Demention
2916 East Upper Hayden Lake Road
Hayden Lake, ID 83835
(208) 762-0762
"smrtalec" <smrtalec_NO_SPAM@algxmail.com> wrote in message
news:3vUZb.21103$wD5.18798@nwrddc03.gnilink.net...
>
>
> I have a script which function is to parse through a comma seperated data
> file, check if the entry is already existing, then if not enter the data
> into a mysql table. However, it only seems to be finding a match on the
> third time around. ie if 'john brown' is in the data file it will only
> recognise it as a match the second 'john brown'. It would almost seem the
> data from the previous row though inserted has not been registered. see
code
> snippet below
>
> <snippet>
> #! /usr/bin/perl -w
>
> use DBI;
>
>
> read_file();
>
> sub insert_data {
> my @$value = @_;
> my $rdate=get_date();
> my $p01=$dbh->quote ("0"); # own_id
> my $p02=$dbh->quote ($rdate); # prop_date_lmod
>
> ...........repetive code removed.................
>
> my $p12=$dbh->quote ($value->[9]); # own_mobile_phone
> my $sql = "INSERT INTO owner_info_inglewood
> VALUES ($p01,$p02,$p03,$p04,$p05,$p06,
> $p07,$p08,$p09,$p10,$p11,$p12
> );";
>
> my $sth_i = $dbh->prepare ($sql) or err_trap("failed to prepare
> statement\n");
> $sth_i->execute() or err_trap("failed to execute statement\n");
> $sth_i->finish();
> $dbh->commit() or err_trap("failed to execute statement\n");
> }
>
> sub verify_row {
> my @$vrow = @_;
> my $name_l = $dbh->quote($vrow->[0]);
> my $name_f = $dbh->quote($vrow->[1]);
> my $own_str_addr = $dbh->quote($vrow->[4]);
> my $own_city_addr = $dbh->quote($vrow->[5]);
> ## query property info table to retrieve property id.
> my $sql = ("SELECT own_name_l,own_name_f,
> own_str_addr,own_city_addr
> FROM owner_info_inglewood
> WHERE own_name_l LIKE $name_l
> AND own_name_f LIKE $name_f
> AND own_str_addr LIKE $own_str_addr
> AND own_city_addr LIKE $own_city_addr;")
> or err_trap('failed to prepare statement\n');
> my $sth_v = $dbh->prepare ($sql) or err_trap("failed to prepare
> statement\n");
> $sth_v->execute or err_trap("failed to execute statement\n");
> my @own_name = $sth_v->fetchrow();
> $sth_v->finish();
> return @own_name;
>
> }
>
> sub read_file {
> my @own_name;
> open (SDDB, "/home/rowan/perl/ho_info.csv") || die print "::$!\n";
> $dbh = connect_try("rowan","******");
> while (<SDDB>) {
> chomp $_;
> my $row = [(split (/,/,$_))];
> ## verify existance of property and retrieve property id.
> unless (verify_row(@$row)) {
> my $frow = format_data(@$row);
> insert_data(@$frow);
> }else{
> @own_name = verify_row(@$row);
> print "read_file::duplicate found ->
> $own_name[0],$own_name[1],$own_name[2],$own_name[3]\n";
> print "read_file::duplicate original->
> $row->[0],$row->[1],$row->[4],$row->[5]\n";
> }
> }
> $dbh->disconnect or err_trap("failed to disconnect statement\n");
> close SDDB;
> }
>
> sub connect_try {
> my ($db_user,$db_password) = @_;
> my $dbh = DBI->connect("dbi:mysql:studio_3:67.**.**.**", "$db_user",
> "$db_password",{AutoCommit => 0 }) or
> err_trap("error connecting to DB");
> return $dbh;
> }
>
> </snippet
>
>
>
> +++++++++++++++++++++++++++++++
> ++REMOVE _NO_SPAM from return ++
> ++e-mail address in order to respond. ++
> +++++++++++++++++++++++++++++++
>
>
------------------------------
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 6184
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