In [1]:

    

s = set()
s, type(s)


    

    
Out[1]:





(set(), set)

In [2]:

    

s = {2, 3, 5, 7}
s, type(s)


    

    
Out[2]:





({2, 3, 5, 7}, set)

In [3]:

    

s = {}
s, type(s)


    

    
Out[3]:





({}, dict)

In [4]:

    

s = {,}
s, type(s)


    

    




  File "<ipython-input-4-a395a77feb02>", line 1
    s = {,}
         ^
SyntaxError: invalid syntax

In [5]:

    

s = set()
s, type(s)


    

    
Out[5]:





(set(), set)

In [6]:

    

2 in s


    

    
Out[6]:





False

In [7]:

    

s |= 2


    

    




---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-7-fdf6d48f382e> in <module>()
----> 1 s |= 2

TypeError: unsupported operand type(s) for |=: 'set' and 'int'

In [8]:

    

s |= {2}
s, type(s)


    

    
Out[8]:





({2}, set)

In [9]:

    

s |= {3}
s, type(s)


    

    
Out[9]:





({2, 3}, set)

In [10]:

    

s.remove(3)
s


    

    
Out[10]:





{2}

In [11]:

    

t = {i:i*i for i in range(5)}
t


    

    
Out[11]:





{0: 0, 1: 1, 2: 4, 3: 9, 4: 16}

In [12]:

    

t.pop(2)


    

    
Out[12]:





4

In [13]:

    

t


    

    
Out[13]:





{0: 0, 1: 1, 3: 9, 4: 16}

In [14]:

    

t.pop(2)


    

    




---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
<ipython-input-14-bc132d9fb9e8> in <module>()
----> 1 t.pop(2)

KeyError: 2