@_=(4,-16,17,-12.4,9,-13.17,-8.14,8,-19.4,0,18,14,-20.17,5,6,11
,-7.19,10,2,3,1,-15.7);do{($=,$-)=(@_[$_]>=0?(-@_[$_],$_):split
/\./,@_[$_]);$$[-$=]=pack q#C#,$-+=65;}foreach(0..$#_);print@$;

# becomes. Note the # comments on some lines
@_ =  #  @_ is a special list variable, thus =( implies a list.
  ( 4,-16,17,-12.4,9,-13.17,  # big list of data... 22 in fact
   -8.14,8,-19.4,0,18,14,     # lots of decimals
   -20.17,5,6,11,-7.19,       # lots of negatives
    10,2,3,1,-15.7 );         # ); is end of list.
do { # do turns a block into a statement that can take loop modifiers
   ($=,$-)=          # $= and $- are print format variables 
                     # wrapped in parens, they want a list.
      (              # ahh, a paren for a list!
         @_[$_] >= 0            # Conditional test for the ?: operator tests for negative
         ? ( -@_[$_], $_ )      # If true, return a list of -neg value, counter
         : split /\./ , @_[$_]  # If false, split on . 
      );             # end of assignment list
   $$[-$=] =         # oh god is @$ a legal array? *sob* yes...
                     # what does a negative array count do?
      pack q#C#, $- += 65;  # pack 'C' is for unsigned chars
                            # 65 is the offest to lowercase 'a' in ascii
} foreach (0..$#_);    #loop modifier for do block      
                       #loops from 0 to 21, the size of @_
print @$;    #print the array!