import string star_list = ['Elizabeth Taylor', 'Bette Davis', 'Hugh Grant', 'C. Grant'] star_list.sort(lambda x,y: ( cmp(string.split(x)[-1], string.split(y)[-1]) or # Sort by last name ... cmp(x, y))) # ... then by first name print "Sorted list of stars:" for name in star_list: print name # # "cmp(X, Y)" return 'false' (0) when X and Y compare equal, # so "or" makes the next "cmp()" to be evaluated. # To reverse the sorting order, simply swap X and Y in cmp(). # # This can also be used if we have some other sorting criteria associated with # the elements of the list. We simply build an auxiliary list of tuples # to pack the sorting criteria together with the main elements, then sort and # unpack the result. # def sorting_criterium_1(data): return string.split(data)[-1] # This is again the last name. def sorting_criterium_2(data): return len(data) # This is some fancy sorting criterium. # Pack the auxiliary list: aux_list = map(lambda x: (x, sorting_criterium_1(x), sorting_criterium_2(x)), star_list) # Sort: aux_list.sort(lambda x,y: ( cmp(x[1], y[1]) or # Sort by criteria 1 (last name)... cmp(y[2], x[2]) or # ... then by criteria 2 (in reverse order) ... cmp(x, y))) # ... then by the value in the main list. # Unpack the resulting list: star_list = map(lambda x: x[0], aux_list) print "Another sorted list of stars:" for name in star_list: print name