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
