#! /usr/bin/python


# create and print a list (to be used like an array)
arr = [1,2,3]
print arr
# print the first element of the list
print arr[0]

# create and print a list (to act like a 2d array)
arr2d = [ [0, 1], [2, 3], [4, 5] ]
print arr2d
# print the first element of the list, i.e. the first row of the array
print arr2d[0]
# print the first element that is within the first row 
print arr2d[0][0]

# add a new element to the end of the list (i.e. a new row to the array)
arr.append([6,7])
print arr2d

# add a new element to the end of the first element in the list
#     (i.e. a new value at the end of the first row of the array)
arr2d[0].append(-1)
print arr2d