# is test object id, it is true only if x and y are same objects
l = [1, 2, 3, 4]
l2 = l
l3 = [1, 2, 3, 4]
print(id(l), id(l2)) # same id
 
if l is l2:
	print('l is l2') # print
else:
	print('l is not l2')
 
if l is l3:
	print('l is l3')
else:
	print('l is not l3') # print
			

# ==, compare value
l = [1, 2, 3, 4]
l2 = l
l3 = [1, 2, 3, 4]
 
if l == l2:
	print('l is l2') # print
else:
	print('l is not l2')
 
if l == l3:
	print('l is l3') # print
else:
	print('l is not l3')
			

#!/usr/bin/python
 
l = [1, 2, [3, 4]]
l2 = [1, 2, [3, 4]]
 
print('ID: ', id(l), id(l2)) # l and l2 have different ids

if l == l2:
	print('l == l2')# print
else:
	print('l != l2')
		

#!/usr/bin/python
 
a = 'pub'
b = ''.join(['p', 'u', 'b'])
print(a == b) # True
print(a is b) # False
		

class MyAge:
    def __init__(self, n):
        self.n = n

a1 = MyAge(42)
a2 = MyAge(42)

a1 == a2 # False
        

class MyAge:
    def __init__(self, n):
        self.n = n
        
    def __eq__(self, other):
        if not isinstance(other, MyAge):
            return NotImplemented
        return self.n == other.n

a1 = MyAge(42)
a2 = MyAge(42)

a1 == a2 # True
        

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