[27042] in Perl-Users-Digest
Perl-Users Digest, Issue: 8954 Volume: 10
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Tue Feb 14 21:05:36 2006
Date: Tue, 14 Feb 2006 18:05:05 -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, 14 Feb 2006 Volume: 10 Number: 8954
Today's topics:
Re: arrays tripping me up <matthew.garrish@sympatico.ca>
Re: arrays tripping me up <jgibson@mail.arc.nasa.gov>
Re: Arrays <FJRussonc@earthlink.net>
Re: Arrays robic0
Re: Looking for script setting a pixel marker in an ima <rvtol+news@isolution.nl>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Tue, 14 Feb 2006 17:53:48 -0500
From: "Matt Garrish" <matthew.garrish@sympatico.ca>
Subject: Re: arrays tripping me up
Message-Id: <YbtIf.25913$T35.398649@news20.bellglobal.com>
"Jim Gibson" <jgibson@mail.arc.nasa.gov> wrote in message
news:140220061245553470%jgibson@mail.arc.nasa.gov...
> In article <43f2374f$0$23279$db0fefd9@news.zen.co.uk>, Obantec Support
> <usenet@NOSPAM.obantec.net> wrote:
>
>> Hi
>>
>> i am reading data from a mysql source and i need to on certain lines when
>> a
>> match occurs read the next few lines and output if not blank, then
>> continue
>> the loop.
>>
>> all lines have text except for the odd blank line.
>>
>> i am using
>>
>> $nic_nam="ShowMe";
>>
>> foreach $i (@result)
>> {
>>
>> if ($i=~ m/$nic_nam/) {
>>
>> print "Found SHowMe<br>\n";
>>
>> #now if this matches out put the next few lines while not blank from
>> @results
>> #max is only ever 7 lines.
>>
>> }
>> }
>
> Use a C-style for loop (untested):
>
> for( my $i = 0; $i < @result; $i++ ) {
for my $i (0..$#result) {
This is a Perl group after all... : )
Matt
------------------------------
Date: Tue, 14 Feb 2006 17:27:51 -0800
From: Jim Gibson <jgibson@mail.arc.nasa.gov>
Subject: Re: arrays tripping me up
Message-Id: <140220061727512245%jgibson@mail.arc.nasa.gov>
In article <YbtIf.25913$T35.398649@news20.bellglobal.com>, Matt Garrish
<matthew.garrish@sympatico.ca> wrote:
> "Jim Gibson" <jgibson@mail.arc.nasa.gov> wrote in message
> news:140220061245553470%jgibson@mail.arc.nasa.gov...
> > In article <43f2374f$0$23279$db0fefd9@news.zen.co.uk>, Obantec Support
> > <usenet@NOSPAM.obantec.net> wrote:
[problem processing array]
> >
> > Use a C-style for loop (untested):
> >
> > for( my $i = 0; $i < @result; $i++ ) {
>
[snipped snippet un-snipped:]
> for my $i (0..$#result) {
> if( $result[$i] =~ /$nic_nam/ ) {
> print "Match found: $result[$i];
> while( $result[$i+1] != /^\s*$/ ) {
> print $result[++$i];
> }
> }
> }
>
> This is a Perl group after all... : )
Matt:
Did you try it? Your suggestion doesn't work. The OP wanted to print
non-blank lines occuring in the array after any element matching a
regex was encountered.
I am afraid you have run afoul of the
knee-jerk-reaction-to-C-style-loops syndrome (or what some native
Choctaw speakers might describe as "cargo-cult programming" :^) that
occurs frequently in this group. Fortunately, the inventor of Perl saw
fit to include C-style loops in the language, perhaps for a good
reason.
Jim 45% cat matt.pl
#!/usr/local/bin/perl
use strict;
use warnings;
my @result = ( 1 .. 10 );
print "Matt's buggy loop:\n";
for my $i ( 0 .. $#result ) {
print "$result[$i]\n";
$i++ if( $i % 2 == 0 );
}
print "\nJim's correct loop:\n";
for( my $j = 0; $j < @result; $j++ ) {
print "$result[$j]\n";
$j++ if( $j % 2 == 0 );
}
Jim 46% perl matt.pl
Matt's buggy loop:
1
2
3
4
5
6
7
8
9
10
Jim's correct loop:
1
3
5
7
9
Jim 47%
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------------------------------
Date: Tue, 14 Feb 2006 23:30:52 GMT
From: "Frank J. Russo" <FJRussonc@earthlink.net>
Subject: Re: Arrays
Message-Id: <MKtIf.11464$Nv2.10253@newsread1.news.atl.earthlink.net>
Jim, Thanks, that is the most inspired view and what I was looking for.
And I appreciate you not flaming me.
I have tried a number of thing but not all of them worked. This is the
better way to get to where I want to be.
Followup question: I am feverishly going thru my books / notes / and
documentation but have not located how do I write to a file and read in from
a file a HASH?
I know how to use files I am doing that now but not with a hash.
Thanks again
Frank
"Jim Gibson" <jgibson@mail.arc.nasa.gov> wrote in message
news:140220061212061768%jgibson@mail.arc.nasa.gov...
> In article <9lcIf.15246$rH5.2635@newsread2.news.atl.earthlink.net>,
> Frank J. Russo <FJRussonc@earthlink.net> wrote:
>
>> ? Does Perl handle multilevel (dimension) arrays? I am assuming it does.
>>
>> I am attempting to improve the way data from my program is stored and
>> recovered.
>>
>> If I was working in any other language I would define an array e.g.
>> Calendar(12,5,1).
>>
>> The data I have is 12 months (Jan - Dec) each month can have 4 or 5 dates
>> attached and each date has a single note (string).
>>
>> How would you organize or define this?
>
> I would use a hash. If you only have one note per day, then you don't
> really have a multi-level array problem. I would use a standard date
> format, e.g. yyyy-mm-dd as an index into a hash:
>
> my %notes;
> $notes{'2006-02-14'} = 'Valentines Day';
>
> This might be more efficient than nested array references, particularly
> if you have sparse data with only 4-5 entries per month.
>
> --
> Jim Gibson
>
> Posted Via Usenet.com Premium Usenet Newsgroup Services
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> ** SPEED ** RETENTION ** COMPLETION ** ANONYMITY **
> ----------------------------------------------------------
> http://www.usenet.com
------------------------------
Date: Tue, 14 Feb 2006 16:27:44 -0800
From: robic0
Subject: Re: Arrays
Message-Id: <m6t4v1te75n8gt2bmrg2e1bknlkmj745gr@4ax.com>
On Tue, 14 Feb 2006 03:43:01 GMT, "Frank J. Russo" <FJRussonc@earthlink.net> wrote:
>? Does Perl handle multilevel (dimension) arrays? I am assuming it does.
>
>I am attempting to improve the way data from my program is stored and
>recovered.
>
>If I was working in any other language I would define an array e.g.
>Calendar(12,5,1).
>
>The data I have is 12 months (Jan - Dec) each month can have 4 or 5 dates
>attached and each date has a single note (string).
>
>How would you organize or define this?
>
>Frank
>
You describe something more suitable to record processing,
non-homogenous 3-dimentional arrays always do.
Perhaps something like this...
my @calendar = ();
# calendar array of records
@calendar =
(
# calendar record (structure)
[ 4, # (element 0) month
22, # (element 1) day
2006, # (element 2) year
"this is an important date", # (element 3) # notes
1, # dirty flag
],
# more records
# [],[],[]....
);
# dynamically allocate and add records to calendar
# read records from file or from command line (use split)
my $record = [2,10,2006,'some notes on this date', 1]; # new set dirty flag
push @calendar, $record;
# do some calendar record query
# do some sorts, get all activity on the 22nd of each month for 2006
@calendar = sort {$a->[2] <=> $b->[2]} @calendar;
@calendar = sort {$a->[1] <=> $b->[1]} @calendar;
print "Activity for the 22nd of each month in 2006:\n";
for (@calendar) {
last unless ($_->[2] == 2006);
print "$_->[0],$_->[1],$_->[2]: $_->[3]\n" if ($_->[1] == 22);
}
# append new records to end of file
# open DBCAL for append (assumed, and tab delimiters).
# its assumed its a simple calendar without fixed sizes
# for the records, otherwise its possible to seek and modify
# file data, etc...
for (@calendar) {
if ($_->[4]) {
print DBCAL "$->[0],\t$->[1],\t$->[2],\t$->[3]\n";
}
# if you wish to use whitespace in the context of your record notes, you
# may want to use a unprintable character (or series of such) for
# delimeters. Its easier to reserve the \n as a line delimeter, though
# can work around this several ways.
------------------------------
Date: Wed, 15 Feb 2006 00:56:36 +0100
From: "Dr.Ruud" <rvtol+news@isolution.nl>
Subject: Re: Looking for script setting a pixel marker in an image
Message-Id: <dstuff.14g.1@news.isolution.nl>
GHL schreef:
> I am looking for a script, which is able to set a pixel marker in an
> image file at position x|y (whereas xmax and ymax are the maximum
> width and height of that image in pixels).
> The color value shall be handed over with constant col.
>
> For reason of simplicity the filename does not vary and should be
> filename.ext and the path can be define hardcoded in the script.
>
> It would be of great help if the pointsize of the pixel marker could
> be defined within the script using a numeric value, thus 2 would mean
> the marker is 2x2 pixels in size.
>
> Seems simple but I didn't find a solution to this problem (and my Perl
> knowledge is only very basic...).
>
> +++
>
> Does anyone of you know a script, which can do just this (or even
> more) or can remember where he has seen any (any specific link
> appreciated !) ?
>
> Thanks so much in advance !
Try GD::Simple, http://search.cpan.org/~lds/GD/GD/Simple.pm
--
Affijn, Ruud
"Gewoon is een tijger."
------------------------------
Date: 6 Apr 2001 21:33:47 GMT (Last modified)
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Subject: Digest Administrivia (Last modified: 6 Apr 01)
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End of Perl-Users Digest V10 Issue 8954
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