#!/usr/bin/perl

use strict;
use warnings;

use Data::Dumper;

my @R = ([qw(x y z)], [qw(a b c)], [qw(e f g)], [qw(h i j)]);

print Dumper \@R;

@R = grep { $_->[0] ne 'a' } @R;

print Dumper \@R;