Formatted Strings in Python - Your Guide to Usage

Formatted strings in Python provide an elegant way to insert variable values into text. They improve the readability and maintainability of your code by avoiding the side effects of traditional string concatenation. Here you will learn how to effectively use formatted strings to make your Python programs clearer and more understandable.

Main insights

• There are two main methods to use formatted strings in Python.
• The old method with placeholders and the new method with curly brackets.
• Formatted strings significantly enhance code readability.

Step-by-Step Guide

Old Method of String Formatting

The first method you will learn about is the traditional way of string formatting using placeholders. Suppose you have a user input and want to use it in a greeting text. Let's say the variable name holds the username.

Here we have used %s as a placeholder for a string. When you run this code, you will see that "Hello, Jan" is output. That's the basic idea of the old method.

If you need multiple values in your string, you can do that as well.

With %d you have used the placeholder for a number. In the output, you can see manually set variables in the formatting.

New Method of String Formatting

However, Python has introduced a new, clearer method for formatting strings that is significantly more flexible. This method uses curly brackets {} as placeholders.

The advantage of this method is that you can specify the placeholders in the desired order, regardless of the order of the variables. This makes your code much easier to understand.

Here,:.2f is used to format the weight output to two decimal places.

Positional Parameters

An interesting feature of this new method is the ability to use positional parameters. If you insert multiple variables and want to arrange them in a different order, you can do this by specifying the indices in the curly brackets.

Notice that you now use {1} for name and {0} for weight. This allows you to arrange and display your variables flexibly.

Deepening String Formatting

There are many more ways to customize your formatted output. The options range from specifying widths to specific formats tailored to your needs. I recommend consulting the official Python documentation to explore all available options in detail.

However, the basic idea remains the same: find the method that best fits your use case and use it to increase the efficiency and readability of your code.

Summary - Formatted Strings in Python

In this guide, you learned how to effectively use formatted strings in Python. You learned both the old method with placeholders and the new method of formatted strings with curly brackets and positions. Both methods have their advantages, with the new method providing significantly more flexibility.