Quiz 6(b) Thu 2 Oct 2008

1. Let L be a list of items. Give Python code to reverse the order of the items in L. For example L = ['a', 4, 'u'] becomes ['u', 4, 'a']. You may assume the list is not empty. Do not make any other assumptions on the length of the list.

   Answer:

                n = len(L)
                for i in range(0,n/2):
                   (L[i],L[n-i-1]) = (L[n-i-1],L[i])
   

2. Define a function minus which takes on input one or two numbers. The output of minus(x) is -x and minus(x,y) returns x-y.

   Answer:

             def minus ( x, *y ):
                if len(y) == 0:
                   return -x
                else:
                   return x - y[0]