Perl Guru Forums: Perl Programming Help: Intermediate: Ordering in Perl

CGI/Perl Guide | Learning Center | Forums | Advertise | Login

Site Search: in


	MAIN INDEX	SEARCH POSTS	WHO'S ONLINE	LOG IN

Home: Perl Programming Help: Intermediate:
Ordering in Perl

edesign
Deleted

Mar 4, 2000, 3:28 PM

Post #1 of 6 (1809 views)

Ordering in Perl	Can't Post

Hello! I am currently working on a perl script that takes text files in a directory and pastes them into a webpage. This allows me to easily update the news on my site. I was able to get everything to work, but because it is news, I need the text files to be pasted onto the webpage in order of newest to latest and I cannot figure out how to do it. I currently name the text files in the following format, where 00-00-00 is the date:

00-00-00_File_Name_Here.txt

Could I use the titles to make the script order them? And if not, how else could I do it? Please look at what I already have of the script below, and let me know. Thanks!

-Daniel

#!/usr/bin/perl

$newsdir = '/home/ebeanies/public_html/cgi-bin/news';

print "Content-type: text/html\n\n";

opendir THEDIR, "$newsdir" | | die "Unable to open the news!";
@allfiles = readdir THEDIR;
closedir THEDIR;
foreach $file (@allfiles) {
if ("$newsdir/$file" =~ /\.txt/) {
open (newsdir, "<$newsdir/$file");
@newsdir=<newsdir>;
close(newsdir);
foreach $newsdir (@newsdir) {
print "$newsdir\n";
}
print qq~

<table border="0" cellspacing="0" cellpadding="0" width="100%">
<tr>
<td bgcolor="#ffffff" height="5"><table border="0" cellpadding="0" cellspacing="0"><tr><td></td></tr></table>
</td>
</tr>
<tr>
<td bgcolor="#000000" height="1"><table border="0" cellpadding="0" cellspacing="0"><tr><td></td></tr></table>
</td>
</tr>
<tr>
<td bgcolor="#ffffff" height="5"><table border="0" cellpadding="0" cellspacing="0"><tr><td></td></tr></table>
</td>
</tr>
</table>
 ~;
}
}

summer
Deleted

Mar 5, 2000, 1:32 AM

Post #2 of 6 (1809 views)

Re: Ordering in Perl [In reply to]	Can't Post

Daniel,

You can certainly order by filename.

You haven't specified whether you are using
dates in US, European or Japanese order.

Assuming that all the numbers are exactly 2 digits the following approaches will work:

If you are using Japanese year-month-day you can use ASCII ordering, e.g.

foreach $file ( sort @allfiles ) {

If you are using US month-day-year or European day-month-year then you'll have to
get each part of the date and recombine them in an orderable form; here's an example using US month-day-year:

foreach $file ( sort {
my( $amon, $aday, $ayear ) =
$a =~ /^(\d\d)-(\d\d)-(\d\d)/o ;
my( $bmon, $bday, $byear ) =
$b =~ /^(\d\d)-(\d\d)-(\d\d)/o ;
"$ayear$amon$aday" cmp "$byear$bmon$bday"
} @allfiles ) {

I've used ASCII rather than numeric comparison because I would expect it to be faster.

edesign
Deleted

Mar 5, 2000, 7:48 AM

Post #3 of 6 (1809 views)

Re: Ordering in Perl [In reply to]	Can't Post

Summer,

I am using the US Month-Day-Year form in my script, so each file name looks like this:

Month-Day-Year_File_Name_Here.txt

I think he reason I cannot get it to work is because I add the title of the article onto the date. Would it be possible for the script to only ready the first 8 characters? Let me know. Thanks!

-Daniel

[This message has been edited by edesign (edited 03-05-2000).]

edesign
Deleted

Mar 5, 2000, 12:23 PM

Post #4 of 6 (1809 views)

Re: Ordering in Perl [In reply to]	Can't Post

Summer,

I got it to work! All I did was use a simple sorting function and twisted it around so it would display the newsest dates first, like so:

foreach $file (sort { int($b) <=> int($a) } @allfiles) {

Thanks for the help!

-Daniel

summer
Deleted

Mar 5, 2000, 2:12 PM

Post #5 of 6 (1809 views)

Re: Ordering in Perl [In reply to]	Can't Post

Daniel,

I'm surprised that int() solves the problem!

By using int() on mm-dd-yy_filename.txt I would expect perl to just compare months
since int() will tell it to read digits until
it gets a non-digit and return that as its result.

For testing I'd have files (using US date format) called:
03-15-02_first.txt
02-10-01_second.txt
01-05-00_third.txt
etc.

I'd still suggest that the easiest solution is to use YYYYMMDD-filename.txt format; it will work for all years and you can compare without even bothering with int().

edesign
Deleted

Mar 5, 2000, 5:42 PM

Post #6 of 6 (1809 views)

Re: Ordering in Perl [In reply to]	Can't Post

Summer,

I tried the script out with two different files per month and it seems to be working fine, although I think I am going to switch to the YYYYMMDD_File_Name_Here.txt just to be safe. While we are on the subject, I have another question. In each of my .txt files, I just write each news article in html because many of them use tables, etc. Is it possible to use a chomp feature so each file could look like this:

Article Title
Article Date
Source
Everything below this point is the article

Does that make any sense? Let me know. Thanks!

Search for (options)

Web Applications & Managed Hosting Powered by Gossamer Threads
Visit our Mailing List Archives