Simpler Debugging With F-Strings

In this lesson, you’ll learn how you can accomplish simpler debugging with f-strings. f-strings were introduced in Python 3.6, and have become very popular. They might be the most common reason for Python libraries only being supported on version 3.6 and later. An f-string is a formatted string literal. You can recognize it by the leading f:

>>> style = "formatted"
>>> f"This is a {style} string"
'This is a formatted string'

When you use f-strings, you can enclose variables and even expressions inside curly braces. They will then be evaluated at runtime and included in the string. You can have several expressions in one f-string:

>>> import math
>>> r = 3.6

>>> f"A circle with radius {r} has area {math.pi * r * r:.2f}"
'A circle with radius 3.6 has area 40.72'

In the last expression, {math.pi * r * r:.2f}, you also use a format specifier. Format specifiers are separated from the expressions with a colon.