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Activity 1.6: String Interpolation

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Activity 1.6

String Interpolation

Key Concepts

A Cleaner Way to Combine Text and Variables

f"..." Strings

The Old Way

You've been combining variables into a sentence by passing multiple values to print(), separated by commas.

The Old Way

Demo
score = 95


print("You scored", score, "%.")
Demo
You scored 95 %.

Notice the awkward space before %. — commas always insert a space, whether you want one or not.

f-Strings

Place an f right before the opening quote, then wrap a variable name in curly braces { } to insert its value directly into the string.

f-Strings

Demo
score = 95


print(f"You scored {score}%.")
Demo
You scored 95%.

Expressions Inside Braces

You can put more than a plain variable inside { } — a full expression works too, and Python evaluates it before inserting the result.

Expressions Inside Braces

Demo
health = 100
damage = 35


print(f"After the attack, you have {health - damage} HP left.")
Demo
After the attack, you have 65 HP left.

Today's Objectives

  • Writing f-strings
  • Inserting variables into a sentence
  • Embedding expressions directly inside { }

Key Terms

f-String
A string prefixed with f that can insert variables or expressions directly inside it.
Placeholder
The { } spot inside an f-string where a value gets inserted.
String Interpolation
Inserting a variable's value directly into a string.

'F' → Fullscreen

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Build

Create a new Python program named 1-6-interpolation.

Task 1: Introduce Yourself

  • Create name and age variables.
  • Print an f-string that introduces yourself using both variables.
String Interpolation
name = "Anthony"
age = 35


print(f"My name is {name} and I am {age} years old.")
#

Task 2: Do Some Math Inline

  • Create score and bonus variables.
  • Print an f-string that adds the two variables together inside the curly braces.
String Interpolation
name = "Anthony"
age = 35


print(f"My name is {name} and I am {age} years old.")


score = 40
bonus = 10


print(f"Your final score is {score + bonus} points.")
#

Task 3: Multiple Placeholders

  • Create favorite_color and favorite_number variables.
  • Print a single f-string that uses both variables in one sentence.
String Interpolation
name = "Anthony"
age = 35


print(f"My name is {name} and I am {age} years old.")


score = 40
bonus = 10


print(f"Your final score is {score + bonus} points.")


favorite_color = "green"
favorite_number = 7


print(f"My favorite color is {favorite_color} and my favorite number is {favorite_number}.")
#

Challenge (Optional): Refactor an Old Line

  • Copy a print() statement from Activity 1.5 and rewrite it as an f-string.
  • Confirm both versions produce the same output.
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Checkpoint

Verify your program works correctly.

Example Output
My name is Anthony and I am 35 years old.
Your final score is 50 points.
My favorite color is green and my favorite number is 7.
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Reflection

Answer the following questions before submitting your work.

  1. What is one advantage of an f-string over separating values with commas in print()?
  2. What happens when you place an arithmetic expression, like {score + bonus}, inside an f-string's curly braces?
  3. If you completed the Challenge, did rewriting your Activity 1.5 line as an f-string change its output? Why or why not?
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Submit

Submit the required files to the appropriate dropbox.

Activity Complete