A Deque double-ended queue. It can be visualized similar to a hollow tube or pipe, which is open at the both ends. Deques allows addition and removal of elements from either ends. It will be more clear with examples:

import collections 

de = collections.deque('India')
print 'deque:', de
print 'Lenght :', len(de)
print 'left end:', de[0]
print 'right end:', de[-1]

de.remove('a')

print 'After removing:', de

Here we are providing input to deque 'India' and we are printing the left-hand side and right-hand side elements of deque using the index and then we are removing a character 'a' from the right-hand side of the deque using remove(). The output will look something like this:

The len() function gives the length of the deque.