def strlist_minus(a, b):
 temp = cidict()
 for elt in b:
  temp[elt] = elt
 result = [elt for elt in a if (not temp.has_key(elt))]
 return result

def strlist_minus ( a , b ) : temp = cidict ( ) for elt in b : temp [ elt ] = elt result = [ elt for elt in a if ( not temp . has_key ( elt ) ) ] return result
return list of all items in a which are not in b .