Installation of Python

• Download the current production version of Python (3.6.2) from the Python Download site.
• Double click on the icon of the file that you just downloaded.
• Accept the default options given to you until you get to the Finish button. Your installation is complete.

Setting up the Environment

• Starting at My Computer or This PC go to the following directory C:\Python36. In that folder you should see all the Python files.
• Copy that address starting with C: and ending with 34 and close that window. (Click on the right side of the address bar at the top of the screen to access the text.)
• Click on Start. Right Click on My Computer or This PC. (Do not click on the Desktop icon, it is only a shortcut.)
• Click on Properties. Click on Advanced System Settings or Advanced.
• Click on Environment Variables.
• Under System Variables search for the variable Path.
• Select Path by clicking on it. Click on Edit.
• Scroll all the way to the right of the field called Variable value using the right arrow.
• Add a semi-colon (;) to the end and paste the path (to the Python folder) that you previously copied. Click OK.

Writing Your First Python Program

• Create a folder called CS303E on your C:\ drive. You will be storing all your Python programs in this folder.
• Go to Start and either type Run in the Start Search box at the bootom or click on Run.
• Type in notepad in the field called Open.
• In Notepad type in the following program exactly as written:

# File: Hello.py
def main():
  print ("Hello World!")

main()

• Go to File and click on Save as.
• In the field Save in browse for the C: drive and then select the folder CS303E.
• For the field File name remove everything that is there and type in Hello.py.
• In the field Save as type select All Files
• Click on Save. You have just created your first Python program.

Running Your First Program

• Go to Start and click on Run.
• Type cmd in the Open field and click OK.
• A dark window will appear. Type cd C:\ and hit the key Enter.
• If you type dir you will get a listing of all folders in your C: drive. You should see the folder CS303E that you created.
• Type cd CS303E and hit Enter. It should take you to the CS303E folder.
• Type dir and you should see the file Hello.py.
• To run the program, type python Hello.py and hit Enter.
• You should see the line Hello World!
• Congratulations, you have run your first Python program.

Python comes bundled with Mac OS X. But the version that you have is quite likely an older version. Download the latest binary version of Python that runs on your version of Mac OS X and install it on your system.

If you have an older version of Python on your Mac do NOT uninstall it. You can have various versions of Python without any problems. To run the newer version as a separate command edit or create a .bash_profile in your home directory. You will be in your home directory when you open your terminal window. Add these two lines in it:

# set the path for Python 3
PATH="/Library/Frameworks/Python.framework/Versions/3.6/bin:${PATH}"
export PATH

# set up an alias for the Python 3
alias python3='/Library/Frameworks/Python.framework/Versions/3.6/bin/python3.6'

You can add them by opening a text editor such as nano (you could also use vi or emacs if you are comfortable with those). Perform the following steps to edit your .bash_profile.

Type 'nano .bash_profile' to open the text editor
Add the lines from above by either copying and pasting or typing them in
Press 'ctrl+o' and then 'enter' to save the file
Press 'ctrl+x' to exit the text editor

Restart your computer. Now if you type python in any Terminal window the older version will be called upon and if you type python3 you will be using the newer verson. To check the version you are using, run this command:

python -V

python3 -V

Writing Your First Python Program

• Click on File and then New Finder Window.
• Click on Documents.
• Click on File and then New Folder.
• Call the folder CS303E. You will be storing all class related programs there.
• Click on Applications and then TextEdit.
• Click on TextEdit on the menu bar and select Preferences.
• Select Plain Text.
• Unselect Smart Quotes.
• In the empty TextEdit window type in the following program, exactly as given:

# File: Hello.py
def main():
  print ("Hello World!")

main()

• From the File menu in TextEdit click on Save As.
• In the field Save As: type Hello.py.
• Select Documents and the file folder CS303E.
• Click Save.

Running Your First Program

• Select Applications, then Utilities and Terminal.
• In your Terminal window type ls and Return. It should give a listing of all the top level folders. You should see the Documents folder.
• Type cd Documents and hit Return.
• Type ls and hit Return and you should see the folder CS303E.
• Type cd CS303E and hit Return.
• Type ls and hit return and you should see the file Hello.py.
• To run the program, type python3 Hello.py and hit Return.
• You should see the line Hello World!
• Congratulations, you have run your first Python program.

Starting IDLE on Mac

• In a Terminal window, type python3. This will start the Python shell. The prompt for that is >>>
• At the Python shell prompt type import idlelib.idle
• This will start the IDLE IDE

Using IDLE on either Windows or Mac

• Start IDLE
• Go to File menu and click on New Window
• Type your program in
• Go to File menu and click on Save. Type in filename.py This will save it as a plain text file, which can be opened in in any editor you choose (like Notepad or TextEdit).
• To run your program go to Run and click Run Module