Reference library

Dictionaries & sets

Key–value maps, uniqueness, counting, grouping, and fast lookups.

28 matches

How to Use Dictionaries and Sets in Python for Beginners

Demonstrates Python dictionary operations and set operations with examples, including access, modification, defaults, and set algebra.

dictionary set beginner

Python

def demonstrate_collections():
    # Dictionary basics
    student = {
        "name": "Alice",
        "age": 20,
        "courses": ["Math", "Physics"]
    }
    print("Dictionary:", student)

    # Access and modify
    student["age"] = 21
    student["grade"] = "A"
    print("Modified:", student)

    # Get with d…

11 0 Open

Dictionaries & sets easy

How to Use Dictionaries and Sets in Python for Beginners

Introduces Python dictionaries and sets with practical examples including creating, modifying, and performing set operations, plus a word-frequency counter.

dictionaries sets data structures

Python

def demonstrate_dict_sets():
    # Create a dictionary with basic info
    person = {
        "name": "Alice",
        "age": 30,
        "city": "New York"
    }
    print("Dictionary:", person)

    # Access and modify dictionary values
    person["age"] = 31
    person["email"] = "alice@example.com"
    print("Afte…

15 0 Open

Dictionaries & sets medium

LRU Cache with OrderedDict in Python

Implement an LRU cache using collections.OrderedDict to track insertion order and evict the least-recently-used item when capacity is exceeded.

lru-cache ordereddict caching

Python

from collections import OrderedDict

class LRUCache:
    def __init__(self, capacity):
        self.capacity = capacity
        self.cache = OrderedDict()

    def get(self, key):
        if key not in self.cache:
            return -1
        self.cache.move_to_end(key)
        return self.cache[key]

    def put(sel…

14 0 Open

Dictionaries & sets easy

Validate dictionary data with sets in Python

Validate a dictionary against required keys and allowed value sets, returning a list of validation errors.

dictionaries sets validation

Python

def validate_data(data, required_keys, allowed_values=None):
    """
    Validate a dictionary against required keys and optional allowed value sets.
    Returns a list of validation errors (empty list if valid).
    """
    errors = []
    
    # Check for missing required keys
    missing = set(required_keys) - set(…

15 0 Open

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