sub test {
my @names = (
'jacob',
'alexander',
'ethan',
'andrew',
    );

my @new_names = map(ucfirst, @names);

foreach my $name (@new_names) {
print $name, "\n";
    }
}

my @row_ary = (1, 3, 'abc', undef, 12, 'ddd', undef, undef) ;
map { print } @row_ary;

my @row_ary = (1, 3, 'abc', undef, 12, 'ddd', undef, undef) ;
map { $_='x' unless $_ } @row_ary;

sub test {
my @words = (
'hello',
'123',
'B51',
'123abc',
'8',
    );

my @numbers = grep { /^\d+$/ } @words; 

my @nums = (2, 1, 3, 5, 4, 6);
my @odd = @nums[grep { $_ & 1 } 0..$#nums];