Chapter 6 Practical Exam
Demonstrate your dictionary mastery!
Problem 1: Word Counter
MediumDescription
Create a function count_words(text) that takes a string and returns a dictionary with each word as a key and its count as the value.
- Convert words to lowercase before counting
- Words are separated by spaces
- Return an empty dict for empty string
Example
Hint
Use text.lower().split() to get lowercase words. Loop through and use dict.get(word, 0) + 1 to count.
Problem 2: Grade Calculator
MediumDescription
Create a function calculate_average(grades) that takes a dictionary of student names and their grades (list of numbers) and returns a dictionary with each student's average grade.
- Round averages to 1 decimal place
- Return empty dict for empty input
- Handle students with empty grade lists (average = 0)
Example
Hint
Use dict comprehension: {name: round(sum(scores)/len(scores), 1) if scores else 0 for name, scores in grades.items()}
Problem 3: Inventory Merger
MediumDescription
Create a function merge_inventory(inv1, inv2) that merges two inventory dictionaries. If an item exists in both, add the quantities together.
- Return a new dictionary (don't modify originals)
- Handle empty dictionaries
- Keys are item names, values are quantities
Example
Hint
Start with result = inv1.copy(), then loop through inv2 and add using result[key] = result.get(key, 0) + value.
