python number keys in dictionary code example

Example 1: get number of key in dictionary python

#Call len(obj) with a dictionary as obj to count the number 
#of key-value pairs in the dictionary.

a_dictionary = {"a": 1, "b": 2}
print(len(a_dictionary))

OUTPUT:
2

Example 2: python create a dictionary of integers

>>> dict.fromkeys(range(1, 4))
{1: None, 2: None, 3: None}
>>> dict(zip(range(1, 4), range(1, 4)))
{1: 1, 2: 2, 3: 3}