use strict;
use Data::Dumper;

my $string = 'a, 1, 2,  3';

my @split_comma = split /,/, $string;
print "\@split_comma =>", Dumper(\@split_comma);

my @split_comma_space = split /,\s+/, $string;
print "\@split_comma_space =>", Dumper(\@split_comma_space);