Hi Sri, On Wednesday 03 November 2010 01:04:03 Sri wrote: > Hi > > I am trying to figure out how can we compare two index values of two > strings in the same array, so that if the 1st argument index value is > less than second argument index value, I want to swap the input > arguments.Please help me with that. > I successfully got the index values for the given input ( 2 cities > separated by space). But couldnt compare the indexes . >
You can compare the indexes using </>/<=/>=/<=> etc. and the strings using le/lt/gt/ge/cmp etc. See http://perldoc.perl.org/perlop.html . One option would be for you to check if (($i < $j) xor ($cities[$i] lt $cities[$j])) and hten swap. Some further comments on your code: > My code is > > > #!/usr/local/bin/perl > > use strict; > use warnings; > > my @cities = qw/Atlanta Boston Chicago Denver Detroit Houston LA Miami > NY Philly SanFrancisco Seattle/; > > my ($i, $j); > > for ( $i = 0; $i < @cities; $i++) { > next unless $cities[$i] =~ /\b$ARGV[0]\b/i; > You are interpolating $ARGV[0] into the regex. This will evaluate it as a mini-regex which may be a security problem. You may wish to use \Q and \E. See: http://community.livejournal.com/shlomif_tech/35301.html In your case doing "eq" may work just as well, because each city is a whole word. > print "$i: $cities[$i] \n"; > > } This loop will always put @cities in $i. Do you want to find the first city that matches? In that case, use first from List::Util. > for ( $j = 0; $j < @cities; $j++) { > next unless $cities[$j] =~ /\b$ARGV[1]\b/i; > > print "$j: $cities[$j] \n"; > > } Again - $j will always be @cities. Also see http://perl-begin.org/tutorials/bad-elements/#subroutine-arguments about not subscripting @_ and @ARGV, etc. directly. > > > if ($i > $j) { > > print" $ARGV[0] $ARGV[1] \n"; > > } else { > > print" $ARGV[1] $ARGV[0] \n"; > > } In your case, since the array is sorted, this makes less sense. Regards, Shlomi Fish -- ----------------------------------------------------------------- Shlomi Fish http://www.shlomifish.org/ List of Portability Libraries - http://shlom.in/port-libs <rindolf> She's a hot chick. But she smokes. <go|dfish> She can smoke as long as she's smokin'. Please reply to list if it's a mailing list post - http://shlom.in/reply . -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
