In [2]:

    

a = [1, 2, 3]
b = a
a.append(4)
b


    

    
Out[2]:





[1, 2, 3, 4]

In [3]:

    

class Gizmo:
    def __init__(self):
        print('Gizmo id: %d' % id(self))


    

In [4]:

    

x = Gizmo()


    

    




Gizmo id: 1095113832488

In [5]:

    

y = Gizmo() * 10


    

    




Gizmo id: 1095113832376






    




---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-5-0f524f080953> in <module>()
----> 1 y = Gizmo() * 10

TypeError: unsupported operand type(s) for *: 'Gizmo' and 'int'

In [6]:

    

charles = {'name': 'Charles L. Dodgson', 'born': 1832}


    

In [7]:

    

lewis = charles


    

In [8]:

    

lewis is charles


    

    
Out[8]:





True

In [9]:

    

id(charles), id(lewis)


    

    
Out[9]:





(1095096406280, 1095096406280)

In [10]:

    

lewis['balance'] = 950


    

In [11]:

    

charles


    

    
Out[11]:





{'balance': 950, 'born': 1832, 'name': 'Charles L. Dodgson'}

In [12]:

    

alex = {'name': 'Charles L. Dodgson', 'born': 1832, 'balance':950}


    

In [13]:

    

alex == charles


    

    
Out[13]:





True

In [15]:

    

alex is not charles


    

    
Out[15]:





True

In [16]:

    

t1 = (1, 2, [30, 40])
t2 = (1, 2, [30, 40])
t1 == t2


    

    
Out[16]:





True

In [17]:

    

id(t1[-1])


    

    
Out[17]:





1095111699976

In [18]:

    

t1[-1].append(99)


    

In [19]:

    

t1


    

    
Out[19]:





(1, 2, [30, 40, 99])

In [20]:

    

id(t1[-1])


    

    
Out[20]:





1095111699976

In [21]:

    

t1 == t2


    

    
Out[21]:





False

In [22]:

    

l1 = [3, [55, 44], (7, 8, 9)]
l2 = list(l1)
l2


    

    
Out[22]:





[3, [55, 44], (7, 8, 9)]

In [23]:

    

l2 == l1


    

    
Out[23]:





True

In [24]:

    

l2 is l1


    

    
Out[24]:





False

In [25]:

    

l1 = [3, [66, 55, 44], (7, 8, 9)]
l2 = list(l1)
l1.append(100)
l1[1].remove(55)
print('l1:', l1)
print('l2:', l2)
l2[1] += [33, 22]
l2[2] += (10,11)
print('l1:', l1)
print('l2:', l2)


    

    




l1: [3, [66, 44], (7, 8, 9), 100]
l2: [3, [66, 44], (7, 8, 9)]
l1: [3, [66, 44, 33, 22], (7, 8, 9), 100]
l2: [3, [66, 44, 33, 22], (7, 8, 9, 10, 11)]

In [26]:

    

class Bus:
    
    def __init__(self, passengers=None):
        if passengers is None:
            self.passengers = []
        else:
            self.passengers = list(passengers)
            
    def pick(self, name):
        self.passengers.append(name)
        
    def drop(self, name):
        self.passengers.remove(name)


    

In [27]:

    

import copy


    

In [34]:

    

bus1 = Bus(['Alice','Bill', 'Claire', 'David'])
bus2 = copy.copy(bus1)
bus3 = copy.deepcopy(bus1)
id(bus1), id(bus2), id(bus3)


    

    
Out[34]:





(1095114522184, 1095114522128, 1095114522296)

In [35]:

    

bus1.drop('Bill')
bus2.passengers


    

    
Out[35]:





['Alice', 'Claire', 'David']

In [37]:

    

id(bus1.passengers), id(bus2.passengers), id(bus3.passengers)


    

    
Out[37]:





(1095114547784, 1095114547784, 1095114476232)

In [38]:

    

bus3.passengers


    

    
Out[38]:





['Alice', 'Bill', 'Claire', 'David']

In [39]:

    

a = [10, 20]
b = [a, 30]
a.append(b)
a


    

    
Out[39]:





[10, 20, [[...], 30]]

In [40]:

    

from copy import deepcopy
c = deepcopy(a)
c


    

    
Out[40]:





[10, 20, [[...], 30]]

In [41]:

    

def f(a, b):
    a += b
    return a


    

In [42]:

    

x = 1
y = 2
f(x, y)


    

    
Out[42]:





3

In [43]:

    

x, y


    

    
Out[43]:





(1, 2)

In [44]:

    

x = [1, 2]
y = [3, 4]
f(x, y)


    

    
Out[44]:





[1, 2, 3, 4]

In [45]:

    

x, y


    

    
Out[45]:





([1, 2, 3, 4], [3, 4])

In [46]:

    

t = (10, 20)
u = (30, 40)
f(t, u)


    

    
Out[46]:





(10, 20, 30, 40)

In [47]:

    

t, u


    

    
Out[47]:





((10, 20), (30, 40))

In [48]:

    

class HauntedBus(Bus):
    """A bus model haunted by ghost passengers"""
    
    def __init__(self, passengers=[]):
        self.passengers = passengers


    

In [49]:

    

bus1 = HauntedBus(['Alice', 'Bill'])
bus1.passengers


    

    
Out[49]:





['Alice', 'Bill']

In [50]:

    

bus1.pick('Charlie')
bus1.drop('Alice')
bus1.passengers


    

    
Out[50]:





['Bill', 'Charlie']

In [51]:

    

bus2 = HauntedBus()
bus2.pick('Carrie')
bus2.passengers


    

    
Out[51]:





['Carrie']

In [52]:

    

bus3 = HauntedBus()
bus3.passengers


    

    
Out[52]:





['Carrie']

In [53]:

    

bus3.pick('Dave')
bus2.passengers


    

    
Out[53]:





['Carrie', 'Dave']

In [54]:

    

bus2.passengers is bus3.passengers


    

    
Out[54]:





True

In [55]:

    

bus1.passengers


    

    
Out[55]:





['Bill', 'Charlie']

In [57]:

    

print(dir(HauntedBus.__init__))


    

    




['__annotations__', '__call__', '__class__', '__closure__', '__code__', '__defaults__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__get__', '__getattribute__', '__globals__', '__gt__', '__hash__', '__init__', '__kwdefaults__', '__le__', '__lt__', '__module__', '__name__', '__ne__', '__new__', '__qualname__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__']

In [58]:

    

HauntedBus.__init__.__defaults__


    

    
Out[58]:





(['Carrie', 'Dave'],)

In [59]:

    

HauntedBus.__init__.__defaults__[0] is bus2.passengers


    

    
Out[59]:





True

In [60]:

    

class Twilightbus(Bus):
    """A bus model that makes passengers vanish"""
    
    def __init__(self, passengers=None):
        if passengers is None:
            self.passengers = []
        else:
            self.passengers = passengers


    

In [61]:

    

basketball_team = ['Sue', 'Tina', 'Maya', 'Diana', 'Pat']
bus = Twilightbus(basketball_team)
bus.drop('Tina')
bus.drop('Pat')
basketball_team


    

    
Out[61]:





['Sue', 'Maya', 'Diana']

In [ ]: