Recursion assignment

Question

def swap(aList):

  if len(aList) == 0:
      return 0
  elif len(aList) == 1:
      print(aList[0])
      return aList[0]
  return aList[0] + swap(aList[2:])

aList = [         


        

Answer 1

Why use a 2D array? You are just swapping its members (1D arrays) rather than the characters in your string. Just pass in the string itself - the indexing operator can access each character. Also, remember that the + operator is non-commutative for strings:

def swap(s):
   if len(s) == 0:
      return ""
   elif len(s) == 1:
      return s
   return s[1] + s[0] + swap(s[2:])

print(swap("abcdefgh")) # --> badcfehg