How do you implement “#ifdef” in python?

Question

Programming in C I used to have code sections only used for debugging purposes (logging commands and the like). Those statements could be completely disabled fo

Answer 1

If you are using #ifdef to check for variables that may have been defined in the scope above the current file, you can use exceptions. For example, I have scripts that I want to run differently from within ipython vs outside ipython (show plots vs save plots, for example). So I add

     ipy = False
     try:
        ipy = __IPYTHON__
     except NameError:
        pass

This leaves me with a variable ipy, which tells me whether or not __IPYTHON__ was declared in a scope above my current script. This is the closest parallel I know of for an #ifdef function in Python.

For ipython, this is a great solution. You could use similar constructions in other contexts, in which a calling script sets variable values and the inner scripts check accordingly. Whether or not this makes sense, of course, would depend on your specific use case.