in reply to What is the Regular expression to search for boundry match for two strings?

i hope i've understood your question right: 
#!/usr/bin/perl -w

use strict;

my $length = 6;
my $left = "xfafasfsdfasdfasdsfFOOBAR";
my $right = "FOOBAR4t11";

if ( substr($left,-$length) eq substr($right,0,$length) ) {
    print "Match!\n";
}

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Update: Oh, you asked for a regular expression: 
my $intersect = substr($left,-$length);

if ( $right =~ /^$intersect/ ) {
    print "matched again!\n";
}

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snowcrash //////

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Re: Re: What is the Regular expression to search for boundry match for two strings?
by Anonymous Monk on Apr 03, 2001 at 13:46 UTC
    Thank you very much. This will help me.
    Can we perfom a match by first concating the 2 strings and then querying on it.
       my $left = "xfafasfsdfasdfasdsfFOOBAR";
   my $right = "FOOBAR4t11";
   # my $concat = "xfafasfsdfasdfasdsfFOOBARFOOBAR4t11";
   my $concat = $left,$right;

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    I should be able to hold on to FOOBAR in a back reference so that I can do further manipulation.
    I need it this way because I do not know the size of boundaries which will match and I would like to match the maximum characters possible to match.
    After this match the two sub strings should be concatnated. this concatnated string will have a single copy of FOOBAR in the middle. like 
       my $conc = "xfafasfsdfasdfasdsfFOOBAR4t11";

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    now this concatnated string will need to matched with one more string let us say 
       my $str3 = "AR4t11xysadgsfje";

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    Now AR4t11 will match and the above process is repeated.
    How efficient will this be if I have about sub strings of size about 500 each and I need to compare about 10000 such sequences with each other.

    Thank you.
    braj
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