This was more an experiment in whether it would be possible, than a piece of sound advice...

use 5.010;
use List::MoreUtils qw< part >;

say for
    map {
        my $x = $_;
        sprintf(
            '%s %d,%d',
            $x->[0][0],
            scalar(grep { $_->[1] eq '1_x' } @$x),
            scalar(grep { defined $_->[2] } @$x), 
        )
    }
    part {
        # me thinks List::MoreUtils needs a way to make this simpler
        state $part = 0;
        state $last = undef;
        $part++ if defined $last && $last ne $_->[0];
        $last = $_->[0];
        $part
    }
    map { chomp; [split /\s+/] }
    sort <DATA>;

__DATA__
A 1_x 9_z
A 1_x 
A 1_x g_z
B 2_c 
B 1_x 1_z
C 1_x 1_z
C v_x 8_z
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