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List Behavior in Functions

Let's explore working with lists inside functions. While it's similar to working with numbers, there are a few important details to be aware of.

Lists are mutable, meaning that any changes made to a list inside a function will also affect the original list outside the function if passed directly.

To prevent this, you can use the copy() method with any mutable data type. By doing so, you create a shallow copy of the list, allowing you to modify a duplicate instead of the original. This ensures that changes made within the function don't impact the original list.


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def add_strawberry(original_list):
    list_copy = original_list.copy()  # Create a copy of the original list
    list_copy.append("Strawberry")  # Modify the copied list
    return list_copy

# Original list
fruits = ["Apple", "Banana", "Cherry"]

# Call the function
new_fruits = add_strawberry(fruits)

# Check the results
print("Original list:", fruits)   # ['Apple', 'Banana', 'Cherry']
print("Modified list:", new_fruits)  # ['Apple', 'Banana', 'Cherry', 'Strawberry']

In this example, the original fruits list remains unchanged because copy() was used. Without copy(), modifying the list inside the function would have changed the original fruits list as well.

Task

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Create a function to apply a 10% discount to product prices over $2.00, without changing the original list.

Define a function apply_discount(prices) that takes a list of prices.
Inside the function, make a copy of prices and assign it to prices_copy.
Use a for loop with index iteration (range(len(prices_copy))) to go through the copied list.
If a price is greater than 2.00, apply a 10% discount.
Return the updated prices_copy list.

Output Requirements

The function should return the new list with discounted prices.
Print the result using:
Updated product prices: <$updated_prices>

Note

Use index-based iteration to ensure the list is modified correctly: for index in range(len(prices)): modifies elements directly, unlike for price in prices:.

Solution

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Section 6. Chapter 4

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List Behavior in Functions

Let's explore working with lists inside functions. While it's similar to working with numbers, there are a few important details to be aware of.

Lists are mutable, meaning that any changes made to a list inside a function will also affect the original list outside the function if passed directly.


              1234567891011121314
            
def add_strawberry(original_list):
    list_copy = original_list.copy()  # Create a copy of the original list
    list_copy.append("Strawberry")  # Modify the copied list
    return list_copy

# Original list
fruits = ["Apple", "Banana", "Cherry"]

# Call the function
new_fruits = add_strawberry(fruits)

# Check the results
print("Original list:", fruits)   # ['Apple', 'Banana', 'Cherry']
print("Modified list:", new_fruits)  # ['Apple', 'Banana', 'Cherry', 'Strawberry']

Task

Swipe to start coding

Create a function to apply a 10% discount to product prices over $2.00, without changing the original list.

Define a function apply_discount(prices) that takes a list of prices.
Inside the function, make a copy of prices and assign it to prices_copy.
Use a for loop with index iteration (range(len(prices_copy))) to go through the copied list.
If a price is greater than 2.00, apply a 10% discount.
Return the updated prices_copy list.

Output Requirements

The function should return the new list with discounted prices.
Print the result using:
Updated product prices: <$updated_prices>

Note

Use index-based iteration to ensure the list is modified correctly: for index in range(len(prices)): modifies elements directly, unlike for price in prices:.

Solution

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Everything was clear?

Thanks for your feedback!

Section 6. Chapter 4

Switch to desktop for real-world practiceContinue from where you are using one of the options below