Editing Python in Jupyter

We are going to practice writing and running Python programs (often called "scripts").

TODO:
* Download a sample notebook
* Make sure the notebook is in your desktop (this keeps things simple)
* Open the notebook in jupyter tab in browser.
* Notebook itself should encourage them to run some cells.
* Terminal navigation instructions below should be updated to work for MacOS and Windows


===Download and start your text editor ===
[[File:Macos-anaconda-nav-hub.png|frameless|400px]]

# Launch Anaconda Navigator
# Find the "VSCode" application in the Anaconda Navigator window. If it is not yet installed, click "Install" (this may take a few minutes)
# Launch the VSCode text editor. 

===Write and save a short Python script===

# Click "New file" to start a new, blank text file.
# Add the following line to your new text file:

<pre>
print("Hello World!")
</pre>

# Save the script as <code>hello.py</code> in your Desktop directory. The <code>.py</code> extension indicates that this file contains Python code.

===Run the script===

# Start a new terminal prompt. See the [[Windows terminal navigation|terminal navigation on Windows]] or [[MacOS_terminal_navigation|terminal navigation on Mac]] instructions for the steps to do this. Recall that on Windows a terminal prompt will look like <code>C:\</code> and a Python prompt will look like <code>>>></code>. Make sure you are at a terminal prompt and not a Python prompt; if you are at a Python prompt, you can type <code>exit()</code> on a line by itself and then press enter to exit Python and return to a terminal prompt.
# Navigate to your Desktop directory from a PowerShell terminal prompt, using the <code>ls</code> and <code>cd</code> commands. See the [[Windows terminal navigation|terminal navigation on Windows]] instructions for a refresher on using these commands. Don't hesitate to get help from a mentor on this step if you need it -- it's a new way of navigating around your computer, so it may be unintuitive at first!
# Once you are in your Desktop directory, you'll see <code>hello.py</code> in the output of <code>ls</code>.
# Type

<pre>
python hello.py
</pre>

and press enter. Doing this will cause Python to execute the contents of that script -- it should print "Hello World!" to the screen. What you've done here is run the Python application with an argument -- the name of a file, in this case "hello.py". Python knows that when you give it a file name as an argument, it should execute the contents of the provided file. You get the same result as if you typed

<pre>
print("Hello World!")
</pre>

at a Python prompt and press enter.

===Success===

You created and ran your first Python script!

* When you run the <code>python</code> command by itself, you start a Python prompt. You can execute Python code interactively at that prompt.
* When you run the <code>python</code> command with a file name as an argument, Python executes the Python code in that file.

[[File:Champagne.png|100px]][[File:Party.png|125px]]

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