Function showing list in reverse order

Question

def imprimeDeTrasParaFrente(lista):
    if lista == None :
       return
    imprimeDeTrasParaFrente(lista.proximo)
    print lista,

class Node(object):

   def __init__(self, carga=None, proximo=None):
       self.carga = carga
       self.proximo = proximo

   def __str__(self):
       return str(self.carga)

   no1, no2, no3 = Node(1), Node(2), Node(3)
   no1.proximo, no2.proximo = no2, no3

   imprimeDeTrasParaFrente(no1)

With the function printDeTrasParaFrente() I was able to print the list elements in reverse order, and it only checks whether the list is empty and calls itself with the next node in the list. In my perspective the print function is never called because when the list is empty the function simply returns and ends the program, or I’m wrong?

Answer 1

There is nothing wrong with the logic of your program, it works exactly as you described it: it displays the values contained in the nodes of a chained list iterating from the last node toward the first.

What’s making it not work is the indentation of the blocks, which is something crucial in Python.

For everything to work perfectly, watch out for code indentation:

Reference Wikibooks