This code...

@array = ("12G","1G30G","13G24G");
map { $cntr++ if /G/ } @array;
print "$cntr\n";
[download]

prints 3

However, I'd do it the longer way to be more obvious...

@array = ("12G","1G30G","13G24G");
for (@array) {
   $cntr++ if /G/;
}
print "$cntr\n";
[download]

There is not single function (that I am aware of) that does this
monks?

Update: looks like I got the answer slightly wrong. My result is the number of array elements that have a G in them.
One brute force way of doing it (getting the correct answer) might be...

@array = ("12G","1G30G","13G24G");
$str = join '', @array;
$str =~ s/[^G]//g;
print length($str), "\n";
[download]

This will correctly print 5