Strings and f-Strings

Strings are how Python stores text: names, messages, file paths, anything made of characters. In this lesson you will create strings, pull pieces out of them, and format them with f-strings, the modern way to build text.

What You'll Learn

• Creating strings and joining them
• Indexing and slicing to grab characters or parts
• Formatting values cleanly with f-strings

Creating Strings

Use single or double quotes. Triple quotes hold multi-line text:

Joining and Repeating

+ glues strings together; * repeats them:

Indexing

Each character has a position, starting at 0. Negative numbers count from the end:

Slicing

Grab a range with [start:end]. The start is included, the end is not:

f-Strings: the Best Way to Format

You met f-strings in the Mad-Libs project. They put values (and even expressions) directly inside text:

f-strings can format numbers too. This is how you show clean decimals, percentages, and thousands separators:

Strings Are Immutable

You cannot change a character in place, but you can build a new string:

Key Takeaways

• Strings use single, double, or triple quotes
• Index from 0, or from -1 at the end; slice with [start:end]
• [::-1] reverses a string
• f-strings insert values: f'Hi, {name}'
• Format numbers inside f-strings: :.2f, :,, :.1%