in reply to Re^4: Split a column
in thread ead a file which has three columns and store the content in a hash

Because the hash contains each key just once.
map{substr$_->[0],$_->[1]||0,1}[\*||{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^*ARGV,3]

In Section Seekers of Perl Wisdom