Re^2: how to find particular string and store in to variable

I think you'd want that RE within an if condition, because otherwise the RE could fail to match and you'd load the previous value of $1 into $var


#!/usr/bin/perl

use warnings;
use strict;

my $str = "http://172.20.37.115:8080/se/1.0/provision/subscribers/1989
+68";

$str =~ /.*\/(\d+)$/;
my $var = $1 || '';

print "$var\n";
# prints 198968

my $str2 = http://172.20.37.115:8080/se/1.0/provision/subscribers/foo"
+;
$str2 =~ /.*\/(\d+)$/;
my $var2 = $1 || '';

print "$var2\n";
#prints 198968
[download]

May be better to do:

use warnings;
use strict;

my $str = "http://172.20.37.115:8080/se/1.0/provision/subscribers/1989
+68";

if( $str =~ /.*\/(\d+)$/ ) {
  my $var = $1 || '';

  print "$var\n";
}
[download]

Comment on Re^2: how to find particular string and store in to variable Select or Download Code

Replies are listed 'Best First'.
Re^3: how to find particular string and store in to variable by AnomalousMonk (Archbishop) on Jun 25, 2015 at 13:58 UTC
But I was matching against `(\d) \z` which cannot fail, although it could match an empty string of digits — which can be useful in and of itself! Update:* Interestingly, what is ~~captured~~ \| assigned to `$var` in a statement like `my ($var) = $s =~ m{ (\d+) \z }xms;` is not the same as what is captured to \| not necessarily the same as the value of `$1`: c:\@Work\Perl\monks>perl -wMstrict -le "'zot' =~ m{ (zot) }xms; ;; for my $s ( 'http://172.20.37.115:8080/se/1.0/pro/subs/198968/', 'http://172.20.37.115.8080/se/1.0/pro/123456', ) { my ($var) = $s =~ m{ (\d+) \z }xms; print '$var is ', defined($var) ? '' : 'UN', 'defined'; print qq{'$s' -> '$var' (\$1 is '$1')}; } " $var is UNdefined Use of uninitialized value $var in concatenation (.) or string at -e l +ine 1. 'http://172.20.37.115:8080/se/1.0/pro/subs/198968/' -> '' ($1 is 'zot' +) $var is defined 'http://172.20.37.115.8080/se/1.0/pro/123456' -> '123456' ($1 is '1234 +56') [download] This warrants a bit more research! Give a man a fish: `<%-(-(-(-<`	[reply] [d/l] [select]
Re^4: how to find particular string and store in to variable by 1nickt (Canon) on Jun 25, 2015 at 14:16 UTC
Interestingly, what is captured to $var in a statement like `my ($var) = $s =~ m{ (\d+) \z }xms;` [download] is not the same as what is captured to $1: Isn't that just because the RE didn't match the first time through the loop, so $1 still held 'zot' ? If your RE did match the first time through, $1 would have been reset and would therefore match $var ...	[reply] [d/l]
Re^5: how to find particular string and store in to variable by AnomalousMonk (Archbishop) on Jun 25, 2015 at 14:39 UTC
Isn't that just because the RE didn't match the first time through the loop ... Yes, and I've clarified the language used above a bit. But I still find the difference interesting: a potential pitfall. Give a man a fish: `<%-(-(-(-<`	[reply] [d/l]
Re^6: how to find particular string and store in to variable by 1nickt (Canon) on Jun 25, 2015 at 16:08 UTC
Re^4: how to find particular string and store in to variable by 1nickt (Canon) on Jun 25, 2015 at 14:13 UTC
Anomalous, sorry, my comment was not in response to yours, but to the one above it by Stevieb :-)	[reply]
Re^5: how to find particular string and store in to variable by AnomalousMonk (Archbishop) on Jun 25, 2015 at 14:23 UTC
... you'd want that RE within an `if` condition ... to ... Stevieb ... Ah! In that case, it's a very good point! I hadn't noticed it myself. Give a man a fish: `<%-(-(-(-<`	[reply] [d/l] [select]