Using regex features, maybe a good homework task:
use strict;
use warnings;
my @a=(2,4,7,5,8);
my ($position, $spaces);
# Elements have not " " ("@a" concatenate with spaces)
if ("@a" =~ /(?:^|\ ) # Element searched maybe the first or not
\K # Count previous group matched within ${^PREMATCH} var
(?{
$position=pos;
$spaces= () = ${^PREMATCH} =~ m, ,g;
}) # Next group will be that which are we searching, s
+o
# we take note about where is it and how many space
+s
# should we ignore ("@a" add spaces)
(8) # Element searched
(?:\ |$) # Element searched maybe the last or not
/xpg)
{
print "Position:" ,$position - $spaces, "\n";
}
In your example you can use index function:
my $pos=index (join ("",@array),7);