1.3 Strings and Formatting | Code Scholars Tutoring

How it works

Strings are immutable sequences. Formatted string literals interpolate expressions directly and are the clearest way to build output.

Build messages with formatted literals rather than repeated concatenation.

Common error

Expecting a string method to modify in place. Every one returns a new string.

Worked example

Python

name = "Ada"
score = 7 / 2
print(f"{name}: {score:.2f}")

Output

Ada: 3.50

An f-string inserts expressions into text. The .2f format shows two digits after the decimal point; it changes the display rather than the stored numeric value.

Exercises

1.3.1 · Trace

Determine the exact output and explain the state changes.

Python

word = "Python"
print(word[1:4])
print(word[-1])

Show solution

Output

yth
n

The slice includes indices 1 through 3; index -1 is the last character.

1.3.2 · Write code

Format the price 12.5 as Price: $12.50.

Show solution

Use two decimal places in an f-string.

One valid solution

price = 12.5
print(f"Price: ${price:.2f}")

Expected output

Price: $12.50

Open Python compiler