ch4.py

from collections import Counter

c=Counter({'a':1,'b':3,'c':5,'d':5})
print (c)#Output:Counter({'c': 5, 'd': 5, 'b': 3, 'a': 1})

#getting count of element 'a'
print (c['a'])#Output:1

#getting count of missing elements return 0.
print (c['z'])#Output:0


#deleting elements from the Counter object
del c['b']
print (c)#Output:Counter({'c': 5, 'd': 5, 'a': 1})


#setting count to 0, doesn't remove elements from the Counter object
c['a']=0
print (c)#Output:Counter({'c': 5, 'd': 5, 'a': 0})