Juuggo
4/25/2017 - 2:44 AM

## deep_reverse_list.py

``````# Question 9: Deep Reverse
# Define a procedure, deep_reverse, that takes as input a list,
# and returns a new list that is the deep reverse of the input list.
# This means it reverses all the elements in the list, and if any
# of those elements are lists themselves, reverses all the elements
# in the inner list, all the way down.

# Note: The procedure must not change the input list.

# The procedure is_list below is from Homework 6. It returns True if
# p is a list and False if it is not.

def is_list(p):
return isinstance(p, list)

def deep_reverse(ls):
newlist = [None] * len(ls)
for i in range(0,len(ls)):
if not is_list(ls[i]):
newlist[len(ls)-1-i] = ls[i]
else:
newlist[len(ls)-1-i] = deep_reverse(ls[i])
# print "newlist:"
# print newlist
return newlist

def deep_reverse_teacher_method(p):
if is_list(p):
newlist = []
for i in range(len(p)-1, -1, -1):
newlist.append(deep_reverse_teacher_method(p[i]))
return newlist
else:
return p
#For example,

p = [1, [2, 3, [4, [5, 6]]]]
print deep_reverse(p)
#>>> [[[[6, 5], 4], 3, 2], 1]
print p
#>>> [1, [2, 3, [4, [5, 6]]]]
print ""
q =  [1, [2,3], 4, [5,6]]
print deep_reverse(q)
#>>> [ [6,5], 4, [3, 2], 1]
print q
#>>> [1, [2,3], 4, [5,6]]
``````