change a key in a dictionary python code example

Example 1: change dictionary value python

my_dict  =  {
   'foo': 42,
   'bar': 12.5
}
my_dict['foo']  =  "Hello"
print(my_dict['foo'])
#This will give the output:

'Hello'

Example 2: how to change key to value and versa in python dictionary

dict = {value:key for key, value in dict.items()}