Dictionaries & sets
Key–value maps, uniqueness, counting, grouping, and fast lookups.
How to Build a Gradebook with Python Dictionaries and Sets
Create a gradebook dictionary from student names and grades, find top students with a set comprehension, and add extra credit with a dict comprehension.
def build_gradebook(students, grades):
"""Create a dictionary mapping student names to their grades."""
return dict(zip(students, grades))
def find_top_students(gradebook, passing_grade=60):
"""Return a set of students with grades at or above the passing grade."""
return {name for name, grade in grad…How to Extract Data by Category in Python with Dictionaries and Sets
Use set comprehensions and a defaultdict to extract product names by category and compute total prices per category from a list of dictionaries.
from collections import defaultdict
# Sample data: products with categories and prices
product_data = [
{"name": "Apple", "category": "fruit", "price": 0.50},
{"name": "Banana", "category": "fruit", "price": 0.30},
{"name": "Carrot", "category": "vegetable", "price": 0.80},
{"name": "Bread", "category…Browse by section
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Dictionaries & sets — Python code examples
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This page collects dictionaries & sets snippets — short, copy-ready Python you can paste into our free online IDE and run without installing anything. Each sample includes a plain-English explanation and the full source code.
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