Unlocking the Power of Nested Dictionaries in Python
The Basics of Nested Dictionaries
In Python, a nested dictionary is a collection of dictionaries within a single dictionary. This data structure allows you to store complex and hierarchical data in a flexible and efficient way. A nested dictionary is created by placing dictionaries inside another dictionary, with each inner dictionary having its own key-value pairs.
Building a Nested Dictionary
Let’s create a nested dictionary to store information about people. We’ll start with an empty dictionary called people and add internal dictionaries to it. Each internal dictionary will represent a person, with keys for their name, age, and sex.
people = {
1: {'name': 'John', 'age': 25, 'ex': 'ale'},
2: {'name': 'Jane', 'age': 30, 'ex': 'female'}
}
Accessing Elements in a Nested Dictionary
To access elements in a nested dictionary, you can use indexing syntax ([]) to navigate through the internal dictionaries. For example, to access the value of the name key in the first internal dictionary, you would use people[1]['name'].
print(people[1]['name']) # Output: John
Adding Elements to a Nested Dictionary
You can add new elements to a nested dictionary by assigning a new key-value pair to an internal dictionary. For example, let’s add a new person to the people dictionary.
people[3] = {'name': 'Luna', 'age': 28, 'ex': 'female'}
Deleting Elements from a Nested Dictionary
To delete elements from a nested dictionary, you can use the del statement. For example, let’s remove the married key from the internal dictionaries.
del people[3]['married']
del people[4]['married']
Iterating Through a Nested Dictionary
You can iterate through a nested dictionary using for loops. The first loop iterates through the keys of the outer dictionary, while the second loop iterates through the keys of the internal dictionaries.
for p_id, p_info in people.items():
for key, value in p_info.items():
print(f"{p_id}: {key} = {value}")
Key Takeaways
- A nested dictionary is an unordered collection of dictionaries.
- Slicing a nested dictionary is not possible.
- You can shrink or grow a nested dictionary as needed.
- Like a regular dictionary, a nested dictionary has keys and values.
- Dictionary elements are accessed using keys.
By mastering nested dictionaries, you can unlock new possibilities for storing and manipulating complex data in Python.