How can i get a substring from a String?

sanjay nayak has asked for the wisdom of the Perl Monks concerning the following question:

Hi Monks

Suppose my $qname="_sip._udp.www.google.com"; Can anyone suggest me a suitable function, so that i can extract the "_sip._udp." from the variable $qname and store the rest part(i.e www.google.com) in a variable $qname1.

Regd's
Sanjay

Comment on How can i get a substring from a String?

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Re: How can i get a substring from a String? by JavaFan (Canon) on Oct 16, 2008 at 11:20 UTC
Assuming "_sip._udp." is a fixed string, `substr` comes into mind: `my $qname = "_sip._udp.www.google.com"; my $qname1 = substr $qname, 10;` [download]	[reply] [d/l]
Re: How can i get a substring from a String? by lamp (Chaplain) on Oct 16, 2008 at 11:40 UTC
Use Regex. `$qname="_sip._udp.www.google.com"; $qname =~ m/(_sip\._udp\.)(.)/; $qname1 = $2;` [download] If you want to replace string "_sip._udp." from the variable, you can use the following code. `$qname="_sip._udp.www.google.com"; $qname =~ s/(_sip\._udp\.)(.)/$2/;` [download]	[reply] [d/l] [select]
Re: How can i get a substring from a String? by krusty (Hermit) on Oct 16, 2008 at 11:56 UTC
The solution proposed with substr will work, but only if the preceding characters before www.google.com are always 10 characters long. If that is always the case, then substr will work well. If the character length preceding your URL is variable, may I suggest split and join? `$qname1 = join ".",(split(/\./, $string))[2,3,4];` [download] The code will only work if there are exactly two dot separated strings prior to the url. If that, too, is variable, then perhaps you could try this small modification: `$qname1 = join ".",(split(/\./, $string))[-3,-2,-1];` [download] Cheers, Kristina	[reply] [d/l] [select]
Re^2: How can i get a substring from a String? by Anonymous Monk on Oct 16, 2008 at 13:03 UTC
`#!/usr/bin/perl -- # use strict; use warnings; my $qname = "_sip._udp.www.google.com"; warn substr $qname, index $qname, 'www'; warn substr $qname, length('_udp.') + index $qname, '_udp.'; __END__ www.google.com at substr.index.pl line 9. www.google.com at substr.index.pl line 10.` [download]	[reply] [d/l]
Re: How can i get a substring from a String? by Bloodnok (Vicar) on Oct 16, 2008 at 11:46 UTC
`my ($qname = "_sip._udp.www.google.com") =~ s/(.\.)(www.)/; ($qname, my $qname1) = ($1, $2);` [download] A user level that continues to overstate my experience :-))	[reply] [d/l]
Re^2: How can i get a substring from a String? by ww (Archbishop) on Oct 16, 2008 at 12:06 UTC
Close... but not quite: `use strict; use warnings; # from bloodnok's reply to 717447 # my ($qname = "_sip._udp.www.google.com") =~ s/(.\.)(www.)/; # typo +? Not substitution, which throws an error # ($qname, my $qname1) = ($1, $2); # error: Can't declare scalar assignment in "my" at 717447.pl line 9, +near ") =~" my $qname; $qname = ("_sip._udp.www.google.com") =~ m/(.\.)(www.)/; print "\$1 is: $1 \n \$2 is: $2\n";` [download] Output `$1 is: _sip._udp. $2 is: www.google.com` [download] Update: corrected to clarify initial commented line which has two problems	[reply] [d/l] [select]
Re^3: How can i get a substring from a String? by Bloodnok (Vicar) on Oct 16, 2008 at 14:33 UTC
Bugger!!! TFT ww, that oughta teach me not to post from a perl-less environment !!! .oO(I knew my sig wasn't in vain) A user level that continues to overstate my experience :-))	[reply]

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