> For the complete documentation index, see [llms.txt](https://docs.bcbi.brown.edu/codiac-for-health/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.bcbi.brown.edu/codiac-for-health/computing/python/repl.md).

# REPL

<mark style="color:$primary;">Python comes with a full-featured interactive command-line REPL (read-eval-print loop) built into the</mark> <mark style="color:$primary;"></mark><mark style="color:$primary;">`python`</mark><mark style="color:$primary;">executable. In addition to allowing quick and easy evaluation of Python statements, it has a searchable history, tab-completion, many helpful keybindings, and dedicated help</mark> <mark style="color:$primary;"></mark><mark style="color:$primary;">`?`</mark> <mark style="color:$primary;"></mark><mark style="color:$primary;">and shell modes</mark> <mark style="color:$primary;"></mark><mark style="color:$primary;">`;`</mark><mark style="color:$primary;">.</mark>

This page provides examples of using REPL on the command line

## Python REPL Example (local)

* Type `python` in terminal to launch REPL

<figure><img src="/files/nW3aMCWSxN6TDyh9Yt7v" alt="Terminal screen showing Python launched. >>> print(&#x22;hello world!&#x22;),  output = hello world!;  >>> word = &#x22;test&#x22; >>> print(word), output = test; >>> type(word), output = <class &#x27;str&#x27;>; >>> len(word), output = 4; >>> exit()"><figcaption></figcaption></figure>

## Python REPL Help Pages (local)

* Type "`help`" to enter help pages within REPL
* Type a function from Python to read help pages (ex:`print`)
* Press `q` to quit

<figure><img src="/files/8ZWqsQLqGzoMHrfmmCgn" alt="Terminal screen with Python launched. >>> help(print)"><figcaption></figcaption></figure>

<figure><img src="/files/BDcq7q778AUJEd3tUSUS" alt="Terminal screen with python launched. Output of >>>help(print) = Help on print function"><figcaption></figcaption></figure>

## Resources

* Real Python: [The Python Standard REPL: Try Out Code and Ideas Quickly](https://realpython.com/python-repl/)


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