Re^2: Grabbing numbers from a URL

Thanks so much. Now I'm thoroughly confused. Apparently the code I posted grabs the contents of $itemID which includes a number, but is the entire string like something-1234.html. What I really need to do is simply capture the 4 numbers in the string, or 5 numbers if it is a 5 digit numbers. There would be no other numbers in any of the urls. Perhaps there is a better way to achieve this. Can you tell me what each of these lines do? I think the first line takes the query string and sets it to $url. I'm not sure I know what the second line does.

$url=q|$itemID|; 
$url=~/(\d{4})+\.htm/i;
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Here's what I'm doing. I'm using this recipe in the .htaccess file to run a perl script to display a page, but it displays a .html file in the browser.

RewriteEngine on
RewriteRule ^(.*)$ $1 [nc]
RewriteRule ^(.*)$ /cgi-bin/getpage.pl?itemID=$1
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So in the script getpage.pl, I grab the $itemID with the code above and turn it into a filename. I search the database for a filename field that includes the page. Sometimes it's 1234.html, other times it's something-something-1234.html. It would really be best to simply grab the 1234 but I don't know how to do that.

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Re^3: Grabbing numbers from a URL by kevbot (Vicar) on Jul 09, 2017 at 06:45 UTC
According to Quote and Quote Like Operators, the `q` operator does not interpolate the string. So, this code `$url = q\|$itemID\|;` [download] results in `$url` contains the literal string `$itemID`, not the contents of `$itemID`. To test this out, run the following code `#!/usr/bin/env perl use strict; use warnings; my $itemID = 'something-12345.html'; my $url = q\|$itemID\|; $url =~ /(\d{4,5})\.htm/i; print "Item ID: $itemID\n"; print " URL: $url\n"; my $num = $1; print " NUM: $1\n"; exit;` [download] You should get an error, since there is no number found in the URL. If you change the code to use the `qq` operator, then the string is interpolated, the match succeeds and you get the number in the `$1` capture group variable. `#!/usr/bin/env perl use strict; use warnings; my $itemID = 'something-12345.html'; my $url = qq\|$itemID\|; $url =~ /(\d{4,5})\.htm/i; print "Item ID: $itemID\n"; print " URL: $url\n"; my $num = $1; print " NUM: $1\n"; exit;` [download] If you want a description of regular expression in plain english, then you can use the YAPE::Regex::Explain module. Running this one-liner on your regex `perl -MYAPE::Regex::Explain -E 'say YAPE::Regex::Explain->new("(\d{4}) ++\.htm")->explain();'` [download] The result is Read more... (2 kB) You can compare this to one of the modified regex patterns that I gave you. For example, `perl -MYAPE::Regex::Explain -E 'say YAPE::Regex::Explain->new("(\d{4,5 +})\.htm")->explain();'` [download] Read more... (1475 Bytes)	[reply] [d/l] [select]

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Re^3: Grabbing numbers from a URL
by kevbot (Vicar) on Jul 09, 2017 at 06:45 UTC

Quote and Quote Like Operators

q

$url = q|$itemID|;
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$url

$itemID

#!/usr/bin/env perl

use strict;
use warnings;

my $itemID = 'something-12345.html';
my $url =  q|$itemID|;
$url =~ /(\d{4,5})\.htm/i;
print "Item ID: $itemID\n";
print "    URL: $url\n";
my $num = $1;
print "    NUM: $1\n";
exit;
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qq

$1

#!/usr/bin/env perl

use strict;
use warnings;

my $itemID = 'something-12345.html';
my $url =  qq|$itemID|;
$url =~ /(\d{4,5})\.htm/i;
print "Item ID: $itemID\n";
print "    URL: $url\n";
my $num = $1;
print "    NUM: $1\n";
exit;
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YAPE::Regex::Explain

perl -MYAPE::Regex::Explain -E 'say YAPE::Regex::Explain->new("(\d{4})
++\.htm")->explain();'
[download]