I am using PyCharm 4 for some Python scripting.
When I type:
I can immediately start using items within the arcpy namespace, like the environment & workspace objects.
How does the Python IDE, in this case PyCharm, know about ArcPy?
There is a Help page entitled Importing ArcPy that explains this - I encourage you to visit that page which has more detail than I am quoting:
When using an import statement, Python looks for a module matching that name in the following locations (and in the following order):
- Paths specified in the PYTHONPATH system environment variable
- A set of standard Python folders (the current folder, c:\python2x\lib, c:\python2x\Lib\site-packages, and so on)
- Paths specified inside any .pth file found in 1 and 2