class punto:
  def __init__ (A,x=0,y=0): A(x,y)
  def __call__ (A,x,y):
    A.x=x; A.y=y
  def __str__(A):
    return '%.2f %.2f' %(A.x,A.y)

p=punto()
print p
# 0.00 0.00

p(7,4); print p
# 7.00 4.00
---------------------------------------
  def __getitem__(A,k):
    return A.coeff()[k]
  def __setitem__(A,k,val):
    if k==0: A.x=val
    elif k==1: A.y=val
    elif k==2: A.z=val
  def __contains__(A,x):
    return x in A.coeff()
  def __len__(A): return len(A.coeff())
---------------------------------------
a=vettore(7,3,5)
for x in a: print x,
# 7.0 3.0 5.0

print
a[2]=99; print a, len(a)
# 7.00 3.00 99.00 3
---------------------------------------
class punto:
  def __init__(A,x,y): A.x,A.y=x,y
  def __cmp__(A,B):
    return cmp((A.x,A.y),(B.x,B.y))

p=punto(3,5); q=punto(7,1)
print p<=q
# True
---------------------------------------
def somma (*a):
  return reduce(operator.add,a,0)

def prod (*a):
  return reduce(operator.mul,a,1)

print somma(7,5,8,3)
# 23

print prod(7,5,8,3)
# 840

print map(operator.sub,[8,9,4],[6,1,2])
# [2, 8, 2]

print map(operator.neg,[3,5,8,-9,-3,0])
# [-3, -5, -8, 9, 3, 0]
---------------------------------------
class numero:
  def __init__(A,x): A.x=x
  def __lt__(A,B): print 'Ciao.'

a=numero(6); b=numero(9)
a<b
# Ciao.
---------------------------------------
print type(77)
# <type 'int'>
print isinstance(77,int)
# True

print type([3,5,1])
# <type 'list'>
print isinstance([3,5,1],tuple)
# False

print type('alfa')
# <type 'str'>

def f(x): pass
print type(f)
# <type 'function'>

a=vettore(8,0,2)
print type(a)
# <type 'instance'>
print isinstance(a,vettore)
# True