F-strings

Joining text with + works, but with more values, it becomes hard to read: every number needs str(), and it's easy to forget a space or a quote:

first_name = "Anna"
age = 25
print("My name is " + first_name + " and I am " + str(age) + " years old.")

There is an easier way: an f-string. It's text with the letter f right before the opening quote. You insert a value into it by writing it in curly braces {}:

first_name = "Anna"
age = 25
print(f"My name is {first_name} and I am {age} years old.")

Both examples print:

My name is Anna and I am 25 years old.

Python replaces every {...} with the value inside it, and numbers work without str(). The spaces are part of the text, so you can see right away where they are. The f stands for “formatted”.

You can even put a calculation inside the braces:

price = 120
print(f"Two tickets cost {price * 2} dollars.")

This prints:

Two tickets cost 240 dollars.

Don't forget the f. Without it, the braces are just text, and they are printed as they are:

day = "Monday"
print("Today is {day}.")

This prints:

Today is {day}.

An f-string is a string like any other, so you can also store it in a variable. From now on, we'll use f-strings whenever we put values into text.