update() method to update or add key value pairs to a dictionary

update(), takes one arguments , iterable object.

Returns : Nothing is returned .

The original dictionary is changed after this method.

Adding new key value pair

my_dict={'a':'One','b':'Two','c':'Three'}
my_dict2={'d':'Four'} # new key 
my_dict.update(my_dict2)
print(my_dict)

Output is here

{'a': 'One', 'b': 'Two', 'c': 'Three', 'd': 'Four'}

my_dict={'a':'One','b':'Two','c':'Three'}
my_dict2={'b':'New value'} # existing key 
my_dict.update(my_dict2)
print(my_dict)

Output (key b with New value is updated )

{'a': 'One', 'b': 'New value', 'c': 'Three'}

my_dict={'a':'One','b':'Two','c':'Three'}
my_dict.update(d='Four',e='Five')
print(my_dict)

Output

{'a': 'One', 'b': 'Two', 'c': 'Three', 'd': 'Four', 'e': 'Five'}

We can add new key with values and update existing values by using update()

my_dict={'a':'One','b':'Two','c':'Three'}
my_dict.update(b='New one',d='Four',e='Five')
print(my_dict)

Output ( value of key b is updated and new keys d and e added )

{'a': 'One', 'b': 'New one ', 'c': 'Three', 'd': 'Four', 'e': 'Five'}