Functions, Parameters & Return Values — Lesson 3: Return a string

New skill: String expressions and return types
Previously learned: Unit 02 — data types, variables, expressions

Why this matters

Functions don’t have to return numbers. A function can construct and return a message using text and its inputs.

def tag(name):
    return 'Hi, ' + name

print(tag('Sam'))

The + operator concatenates strings when both sides are text. The returned value has type str.

Before moving on, trace each line of the example by hand. Predict the result before running it in the browser.

Why do you need the space after the comma in 'Hi, '?

return 'Hi, name' returns the literal word name, not the parameter’s value.

Complete create_greeting(username) to return Welcome, <username>! with the actual username inserted. Preserve the exact punctuation.

Example 1 — Input

create_greeting('Riley')

Output

'Welcome, Riley!'

Example 2 — Input

create_greeting('Kai')

Output

'Welcome, Kai!'

Example 3 — Input

create_greeting('')

Output

'Welcome, !'

Starter file: main.py

Use Run to experiment and Check to compare against published examples. A passing public example does not automatically establish mastery.

Hint 1 — Identify the key concept

You can join smaller strings with `+`.

Hint 2 — Find an approach

Use the parameter between the greeting and the exclamation mark.

Hint 3 — Check your answer

The result should be a string returned by the function.

Write a short explanation of why your code works. What input or change would make it behave differently?