max() and min() in Python - Mini Project: Build & Apply

Finding Maximum and Minimum Values with max() and min()

📖 Scenario: You work in a small store and want to find the most expensive and cheapest items in your product list.

🎯 Goal: Build a simple program that finds the maximum and minimum prices from a list of product prices using max() and min().

📋 What You'll Learn

Create a list of product prices

Create variables to hold the maximum and minimum prices

Use max() and min() functions to find the highest and lowest prices

Print the maximum and minimum prices

💡 Why This Matters

🌍 Real World

Stores and businesses often need to find the highest and lowest prices or values quickly to make decisions.

💼 Career

Knowing how to use max() and min() helps in data analysis, reporting, and making smart choices in programming jobs.

1

Create a list of product prices

Create a list called prices with these exact values: 15.99, 23.50, 9.99, 5.49, and 12.00.

Python

# Create the list of prices
# Your code here

Hint

Use square brackets [] to create a list and separate values with commas.

2

Create variables for max and min prices

Create two variables called max_price and min_price and set both to 0.

Python

prices = [15.99, 23.50, 9.99, 5.49, 12.00]
# Create max_price and min_price variables and set them to 0
# Your code here

Hint

Use simple assignment like variable = 0.

3

Find the maximum and minimum prices using max() and min()

Use the max() function on prices and assign the result to max_price. Then use the min() function on prices and assign the result to min_price.

Python

prices = [15.99, 23.50, 9.99, 5.49, 12.00]
max_price = 0
min_price = 0
# Use max() and min() on prices and assign to max_price and min_price
# Your code here

Hint

Use max_price = max(prices) and min_price = min(prices).

4

Print the maximum and minimum prices

Print the values of max_price and min_price exactly as shown: print(max_price) and print(min_price).

Python

prices = [15.99, 23.50, 9.99, 5.49, 12.00]
max_price = max(prices)
min_price = min(prices)
# Print max_price and min_price
# Your code here

Hint

Use two print statements: print(max_price) and print(min_price).

Practice

1. What does the max() function do in Python?

easy

A. Finds the largest item in a list or among values

B. Finds the smallest item in a list or among values

C. Sorts the list in ascending order

D. Removes duplicates from a list

Solution

1. Step 1: Understand the purpose of max()

   The max() function is used to find the biggest or largest item from a list or multiple values.

2. Step 2: Compare with other options

   Options A, C, and D describe different functions or actions, not what max() does.

3. Final Answer:

   Finds the largest item in a list or among values -> Option A

4. Quick Check:

   max() = largest item [OK]

Hint: max() returns the biggest value from inputs [OK]

Common Mistakes:

• Confusing max() with min()
• Thinking max() sorts the list
• Assuming max() removes duplicates

2. Which of the following is the correct way to find the minimum value in a list named nums?

easy

A. minimum(nums)

B. min(nums)

C. nums.min()

D. min = nums

Solution

1. Step 1: Recall the syntax of min()

   The correct syntax to find the smallest value in a list is min(list_name). So, min(nums) is correct.

2. Step 2: Check other options for errors

   minimum(nums) uses a non-existent function minimum(). nums.min() tries to call min() as a method on the list, which is invalid. min = nums assigns min to the list, which is incorrect usage.

3. Final Answer:

   min(nums) -> Option B

4. Quick Check:

   min(list) = smallest value [OK]

Hint: Use min(list_name) to get smallest value [OK]

Common Mistakes:

• Using min as a method like nums.min()
• Trying to assign min to a variable incorrectly
• Using a wrong function name like minimum()

3. What is the output of this code?

numbers = [3, 7, 2, 9, 5]
print(max(numbers))
print(min(numbers))

medium

A. 9 and 2

B. 3 and 5

C. 7 and 2

D. Error

Solution

1. Step 1: Identify the list values

   The list numbers contains [3, 7, 2, 9, 5].

2. Step 2: Find max and min values

   The largest value is 9 and the smallest value is 2.

3. Final Answer:

   9 and 2 -> Option A

4. Quick Check:

   max = 9, min = 2 [OK]

Hint: max() and min() find biggest and smallest values [OK]

Common Mistakes:

• Mixing up max and min results
• Assuming print shows the whole list
• Syntax errors from missing parentheses

4. The following code gives an error. What is the problem?

values = [10, 20, 30]
print(max(values, key=abs))

medium

A. The key function abs() is unnecessary here

B. max() cannot be used with lists

C. The code runs without error and prints 30

D. abs() is not defined

Solution

1. Step 1: Understand max() with key parameter

   The key parameter lets max() compare items by a function result. Here, abs returns absolute values, which are the same as the original values since all are positive.

2. Step 2: Check if code runs correctly

   Since abs is a built-in function and the list is valid, the code runs without error and returns the largest value, 30.

3. Final Answer:

   The code runs without error and prints 30 -> Option C

4. Quick Check:

   max(values, key=abs) = 30 [OK]

Hint: max() with key=abs works fine; abs() is built-in [OK]

Common Mistakes:

• Thinking abs() is undefined
• Believing max() can't use key parameter
• Assuming code causes error

5. Given the list words = ['apple', 'banana', 'grape', 'kiwi'], which code finds the word with the shortest length?

hard

A. max(words)

B. max(words, key=len)

C. min(words)

D. min(words, key=len)

Solution

1. Step 1: Understand the key parameter with len()

   Using key=len tells min() to compare words by their length, not alphabetically.

2. Step 2: Identify shortest word

   Among the words, 'kiwi' has the shortest length (4 letters). So min(words, key=len) returns 'kiwi'.

3. Final Answer:

   min(words, key=len) -> Option D

4. Quick Check:

   min by length = 'kiwi' [OK]

Hint: Use min(list, key=len) to find shortest string [OK]

Common Mistakes:

• Using max() instead of min() for shortest
• Not using key=len and getting alphabetical result
• Assuming min(words) finds shortest word