Now, let's see how we can do this in PyCharm. Navigate to the project we just created (TestScientific) if you are not already there. Again, the interpreter that's currently being used for this project should be Python 3.6, and created using Conda:

1. We will open the settings and go to Project: TestScientific | Project Interpreter, which we already saw when we learned how to install external libraries and packages for our projects.
2. Now, click on the dropdown button in the Project Interpreter prompt in the upper section of the window and select Show All..., as follows. This will show us all the Python interpreters that are available on our system:

3. From here, you will be able to select one of the interpreters that's available to be used by PyCharm projects. As an example, I will choose the Python 3.7 interpreter that was created for the TestDjango project earlier.
4. Click OK and Apply to point our current project to that specific interpreter. For this change to take full effect, we need to relaunch PyCharm.
5. After reopening the PyCharm project, you will notice, in the Python Console and Terminal (using the which python command again), that our interpreter has indeed been changed.

That is how you select and change the interpreter for your PyCharm projects, even after they have already been created. In the next section, we will look into the process of importing external projects into PyCharm.