You may want to print these instructions before proceeding, so that you can refer to them while downloading and installing Python. Or, just keep this document in your browser. You should read each step completely before performing the action that it describes.
This document shows downloading and installing Python 3.4.1 on Mac OS X 10.6 and later. You should download and install the latest Python. The current is Python 3.6.4.
The Python download requires about 18 MB of disk space; keep it on your machine, in case you need to re-install Python. When installed, Python requires about an additional 90 MB of disk space.
The following page will appear in your browser.
An Opening python-3.4.1-macosx10.6.dmg pop-up window will appear.
Click Save File.
The file named python-3.4.1-macosx10.6.dmg should start downloading in your standard download folder (mine was stored in Machintosh HD/Users/pattis/Downloads). This file is about 24 MB so it might take a while to download fully if you are on a slow internet connection (it took me about 10 seconds over a cable modem).
The file should appear as
A file folder named Python 3.4.1 containing the Python.mpkg file will appear.
If the following pop-up window appears
enter you password and click Install Python
An Install Python pop-up window will appear.
A new Install Python pop-up window will appear.
A new Install Python pop-up window will appear.
A new pop-up window asking you to agree to the license terms will appear.
A new Install Python pop-up window will appear.
The Python Interpreter and all its libraries occupy about 89 Mb.
By default Python will be installed in your Hard Disk Drive Machintosh HD/Applications/Python3.4. Unless you have a good reason to use another directory, use this one.
The previous pop-window will reappear, displaying the message
Install Python 3.4.1
Please wait while the Installer installs
Python 3.4.1. This may take
several minutes.
During installation, it will show the various operations it is performing and a progress bar for each one.
Eventually a new Install Python pop-up window will appear.
Python should now be installed. To try to verify installation, navigate to the directory Machintosh HD/Applications/Python3.4 (or to whatever directory on which you installed Python) double-click the icon/file IDLE. The following pop-up window will appear.
A pop-up window with the title *Python 3.4.1 Shell* appears, and inside the window on the first line is the text Python 3.4.1 ....
Click the red (terminate) icon to terminate this pop-up window.
You should keep the file python-3.4.1-macosx10.6.dmg somewhere on your computer in case you need to reinstall Python (not likely necessary).
You may now follow the instructions to download and install Java (it is already installed on most Macs; to update Java on your Mac, go to Java SE Development Kit 7 Downloads, Accept the license agreement, and then download dk-7u72-macosx-x64.dmg and install it) and then download/install the Eclipse IDE (for Python).