Your question is confusing. I suspect that you want to know how many "capitals" you have in the string? The scalar value of an array is the number of elements that it contains.

#!/usr/bin/perl
use strict;
use warnings;

my @strings = ('London, Paris','','London');

foreach my $string (@strings)
{
   my @capitals= split(/,/,$string); 

   print "list of capitals: @capitals\n";
   print "number of capitals:".@capitals."\n";
   print "number of capitals:",scalar @capitals,"\n";
   print "lots of capitals\n\n" if (@capitals>1);
   print "one or no capitals\n\n" if (@capitals <= 1);
}

__END__
list of capitals: London  Paris
number of capitals:2
number of capitals:2
lots of capitals

list of capitals: 
number of capitals:0
number of capitals:0
one or no capitals

list of capitals: London
number of capitals:1
number of capitals:1
one or no capitals
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