# exp3.py   example file  more complete structure, list, arrays, matrix
import math
from numpy import array  # for vector and matrix

def main():
  print "exp3.py running"
  a_list=[7, 7.25, "abc"]  # any types
  print "a_list=",
  print a_list
  print "a_list[2]=",      # selecting item 2, start with 0
  print a_list[2]
  a_list.append("def")     # append to end of list
  print "append=",
  print a_list
  del a_list[1]            # delete a selected item
  print "delete=",
  print a_list
  print "len(a_list)=",
  print len(a_list)        # get the length of a list
  print " "

  a_tuple=2, 3, 5, 7   # can not modify  all same type
  b_tuple=(2, 3, 5, 7) # same data as above   all same type
  print "a_tuple=",
  print a_tuple
  print "b_tuple=",
  print b_tuple
  print "b_tuple[2]=", # select item 2 for printing
  print b_tuple[2]
  # b_tuple[2] = 9     # no modify selected item
  print " "

  dict={1:'a', 2:'b', 3:'c'} # dictionary key : value
  print "dict=",
  print dict
  dict[5]='e'
  print "dict 5=",
  print dict
  print "dict[3]=", # look up by key
  print dict[3]
  print " "

  z=range(5)            # zero based, length 5, no 5
  print "range(5)=",
  print z
  z=range(1,5)          # 1 based, length 4, no 5
  print "range(1,5)=",
  print z
  z=range(1,7,2)        # step size 2, no 7
  print "range(1,7,2)=",
  print z
  print " "

  Y = array([0.0 for i in range(4)]) # initialize to zero
  print "array([0.0 for i in range(4)])="
  print Y
  A = array([[1.0 for j in range(4)] for i in range(3)]) # initialize to 1
  print "array([1.0 for j in range(4)] for i in range(3)])="
  print A
  A[2,3] = 2.0
  print "A[2,3] = 2.0"
  print A
  print " "
  
if __name__ == '__main__':
  main()