Join us and get access to thousands of tutorials and a community of expert Pythonistas.

This lesson is for members only. Join us and get access to thousands of tutorials and a community of expert Pythonistas.

Unlock This Lesson

Python String Formatting: Recap & Summary

Python String Formatting Tips & Best Practices Paul Mealus 01:21

Summary of what you’ve learned in this course:

String Format with %
String Format with .format()
f-strings
Template Strings

Knowing which method to use to format strings can be confusing, In this lesson you’ll see a handy flowchart to help you decide which formatting method to use.

Congratulations, you made it to the end of the course! Make it stick: Mentor AI will check what you’ve got down, help you build something with it, and find your #1 takeaway to share in the discussion.

Or go straight to the discussion section and share your #1 takeaway and how you’ll put your new skills to use.

00:01 In this series, we’ve covered the four major ways of string formatting. The first was string formatting with the interpolation operator (%), the second string formatting with the .format() method, the third was f-strings, and the fourth was template strings.

00:18 The thing that these four major ways of string formatting all have in common is that you have to indicate where in the string you’re going to substitute your variables. With the interpolation operator, it’s the interpolation operator. With .format(), it’s curly brackets. With f-strings, it’s curly brackets containing a keyword.

00:40 And with template strings, it’s a dollar sign ($) followed by a keyword. If you’re like me, when you first learned all these it was tough to remember which one to use and when, so I’ve got a quick flow chart to show you.

00:55 Starting at the top, are there user-supplied format strings? If yes, consider using template strings. If not, are you on Python 3.6? If yes, consider using f-strings.

01:09 If not, use the .format() method. Give yourself a pat on the back, you did it! You got through all four major ways of string formatting and best practices!

Malef on April 14, 2019

Thank for straightforward and informative way of presenting information.

adriaprat on April 15, 2019

As philraffsr said, some decimal/left-right justification/zero-fill examples would be nice. 😉

gracebr28 on June 4, 2019

Thanks for the great tutorial!

Stephen Paden on June 27, 2019

Very informative!

aradim on July 14, 2019

Very nice! Thank you.

Pakorn on Dec. 17, 2019

great tutorial

alvesmig on June 28, 2020

Thank you for this great tutorial

dannysharkey80 on Aug. 13, 2020

What is meant by a “user supplied format string”? I’m not sure understand the use-case.

Bartosz Zaczyński RP Team on Aug. 14, 2020

User-supplied strings would be anything that comes from your application’s users rather than you as the author. It could be a comment left on a website or something typed on the keyboard in a command-line app.

For security reasons, you should always assume that such external content may potentially contain malicious data that requires special treatment. Using a template string is safer than all the other methods because it has some countermeasures to prevent the attacks.

Yvonne Wilmot on Sept. 23, 2020

Thanks a lot. That clarified where the different ways of string formatting fit in and when/where each method is supposed to be used.

Become a Member to join the conversation.