Which Version Do You Need?
Unfortunately, there was a significant update to Python several years ago that created a big split between Python versions. This can make things a bit confusing to newcomers, but don’t worry. We’ll walk you through installing both major versions. When you visit the Python for Windows download page, you’ll immediately see the division. Right at the top, square and center, the repository asks if you want the latest release of Python 2 or Python 3.
You can download just Python 2 or Python 3 if you’re sure you only need a particular version. We’re going the distance today and will be installing both of them, so we recommend you download both versions and do the same. Under the main entry for both versions you’ll see an “x86-64” installer, as seen below.
Python installation
If you want to learn the newest version of Python, you’ll need to install Python 3. You can install it alongside Python 2.7 with no problems, so go ahead and download and run the installer now.
On the first screen, enable the “Add Python 3.6 to PATH” option and then click “Install Now.”
Next, you have a decision to make. Clicking the “Disable path length limit” option removes the limitation on the MAX_PATH variable. This change won’t break anything, but will allow Python to use long path names. Since many Python programmers are working in Linux and other *nix systems where path name length isn’t an issue, turning this on in advance can help smooth over any path-related issues you might have while working in Windows.
If you’re only installing Python 3, you can use the same command line trick of typing
python -v
that we used above to check that it is installed correctly and the path variable is set. If you’re installing both versions, however, you need to make the quick tweak found in the following section.
Adjust System Variables So You Can Access Both Python Versions From the Command Line
This section of the tutorial is completely optional, but will allow you to quickly access both versions of Python from the command line. After installing both versions of Python, you may have noticed a little quirk. Even though we enabled the system path for both Python installations, typing “python” at the command prompt only points you to Python 2.7.
The reason for this is simple: the variable (whether automatically adjusted by an installer or manually tweaked) simply points at a directory, and every executable in that directory becomes a command line command. If there are two directories listed and both have a “python.exe” file in them, whichever directory is higher in the list of variables gets used. And, if there is a variable set for the system and the user, the system path takes precedence over the user path.
The latter is exactly what’s happening in this case: the Python 2 installer edited the system wide variable and the Python 3 installer added a user level variable—and we can confirm this by looking at the Windows’ environment variables.
Hit Start, type “advanced system settings,” and then select the “View advanced system settings” option. In the “System Properties” window that opens, on the “Advanced” tab, click the “Environment Variables” button.
Here, you can see Python 3 listed in the “User variables” section and Python 2 listed in the “System variables” section.
There are a few ways you can remedy this situation. The simplest (albeit the one with the least functionality) is to just remove the entry for the version of Python you plan on using the least. While that’s simple, it’s also not very much fun. Instead we can make another change that will give us access to “python” for Python 2 and “python3” for Python 3.
To do this, fire up File Manager and head to the folder where you installed Python 3
(C:\Users\[username]\AppData\Local\Programs\Python\Python36 by default).
Make a copy of the “python.exe” file, and rename that copy (not the original) to “python3.exe”.
Open a new command prompt (the environmental variables refresh with each new command prompt you open), and type “python3 –version”.
Boom! You can now use the “python” command at the Command Prompt when you want to use Python 2.7 and the “python3” command when you want to use Python 3.