REPL

What is REPL?#

REPL stands for Read-Eval-Print Loop. It is a simple, interactive programming environment that takes single user inputs (i.e., single expressions), evaluates them, and returns the result to the user.

A REPL environment comprises the following steps:

1. Read: It reads the inputs given by the user.
2. Evaluate: It evaluates the input expressions, i.e., it processes the code.
3. Print: It prints out the result of the code execution.
4. Loop: It continues the process until the user decides to exit the environment.

Python REPL: The Interactive Shell#

Python includes an interactive shell that is a REPL. It’s a great place for experimenting with new ideas or debugging by seeing the effect of isolated lines of code.

When you type python (or python3 depending on your installation) into your command prompt without any files, you interact with the Python interpreter directly in an ongoing conversation, hence the term interactive shell.

python

Once the Python REPL environment is invoked, it lets you type Python codes on a prompt (designated as >>>), then reads and executes the code, and displays the results.

Here is an example:

1>>> print("Hello, Codebay!")
2Hello, Codebay!

Exiting the REPL#

To get out of the Python REPL, you can either type exit() and press enter or use the keyboard shortcut Ctrl + D.

Advantages of REPL#

The REPL has many benefits:

• It allows immediate feedback/iteration. This means when you type an expression and press “enter,” you immediately get to see the result.
• It’s great for experiments, learning, and debugging.
• You can test snippets of your code without executing the whole script or program.

That’s it! Now you know what a REPL is! It’s a great tool to have in your toolbox as a Python developer. Try to incorporate it into your daily coding tasks.