In [1]:

    

from collections import deque


    

In [2]:

    

d = deque(['l', 'm', 'n'], 3)
print(d)


    

    




deque(['l', 'm', 'n'], maxlen=3)

In [3]:

    

d.append('o')
print(d)


    

    




deque(['m', 'n', 'o'], maxlen=3)

In [4]:

    

d.appendleft('l')
print(d)


    

    




deque(['l', 'm', 'n'], maxlen=3)

In [5]:

    

d.extend(['o', 'p'])
print(d)


    

    




deque(['n', 'o', 'p'], maxlen=3)

In [6]:

    

d.extendleft(['m', 'l'])
print(d)


    

    




deque(['l', 'm', 'n'], maxlen=3)

In [7]:

    

# d.insert(0, 'XXX')
# IndexError: deque already at its maximum size


    

In [8]:

    

print(d.pop())


    

    




n

In [9]:

    

print(d)


    

    




deque(['l', 'm'], maxlen=3)

In [10]:

    

d.insert(1, 'XXX')
print(d)


    

    




deque(['l', 'XXX', 'm'], maxlen=3)

In [11]:

    

print(d.maxlen)


    

    




3

In [12]:

    

# d.maxlen = 5
# AttributeError: attribute 'maxlen' of 'collections.deque' objects is not writable