Question

Is there a way to do the following preprocessor directives in Python?

#if DEBUG  < do some code >  #else  < do some other code >  #endif 

Answer 1

There’s __debug__, which is a special value that the compiler does preprocess.

if __debug__:   print 'If this prints, you're not running python -O.' else:   print 'If this prints, you are running python -O!' 

__debug__ will be replaced with a constant 0 or 1 by the compiler, and the optimizer will remove any if 0: lines before your source is interpreted.