Dictionary Basics
Creating and using dictionaries
Interview Relevant: Key-value storage
Dictionary Basics
Dictionaries store key-value pairs with O(1) lookup.
Code Examples
Basic dictionary operations.
python
1# Create dictionaries
2empty = {}
3person = {"name": "Alice", "age": 25}
4from_pairs = dict([("a", 1), ("b", 2)])
5from_kwargs = dict(name="Alice", age=25)
6
7# Access values
8person["name"] # "Alice"
9person.get("name") # "Alice"
10person.get("city", "Unknown") # Default if missing
11
12# Modify
13person["age"] = 26
14person["city"] = "NYC"
15
16# Delete
17del person["city"]
18person.pop("age") # Returns and removes
19
20# Check key exists
21"name" in person # True
22
23# Length
24len(person)