How about using the powers of join, map and split? 
#!/usr/bin/perl -wT
use strict;

my $input = "word+word+word";
my $i=1;
my $string = join '&',
             map {"keyword".$i++."=$_"}
             split /\+/, $input;
print "$string\n";

__END__
keyword1=word&keyword2=word&keyword3=word

[download]
Reading that complicated line from bottom to top... First we split the string into pieces, then we map those pieces to the new format, finally we join them together with a new delimiter.

Update: Just for kicks... this regex seems to work as well:

my $i = '';
(my $string = $input) =~ s/(^|\+)/($i++&&'&')."keyword$i="/ge;

[download]

-Blake

In reply to Re: splitting contents of a variable ( not what you think!! ) by blakem
in thread splitting contents of a variable ( not what you think!! ) by larwilliams

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