Nested Imports - Printable Version

Nested Imports - Printable Version

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Nested Imports - CanadaGuy - Nov-07-2018

I'm trying to create modules for my application that are themselves testable on their own. I would like to have the following directory structure:

\application.py
\support\module1.py
\support\module2.py

application.py depends on both module1.py and module2.py.
module1.py is also dependent directly on module2.py

My way to make this work so far is the following in module1.py

if __name__ == "__main__":
    import module2
else:    
    import support.module2

Without that, I get various "module not found" issues. I did a lot of reading on absolute and relative imports, but I can't identify my case among the many examples presented. My alternative plan was to leave everything flat for now (no directories) so that imports are nice and straightforward. But for a larger application, I know this would just make a big mess.

Ideas?

RE: Nested Imports - Larz60+ - Nov-07-2018

use try except, here's an extreme example from the lxml manual:

try:
	from lxml import etree
	print("running with lxml.etree")
except ImportError:
	try:
		# Python 2.5
		import xml.etree.cElementTree as etree
		print("running with cElementTree on Python 2.5+")
	except ImportError:
		try:
			# Python 2.5
			import xml.etree.ElementTree as etree
			print("running with ElementTree on Python 2.5+")
		except ImportError:
			try:
				# normal cElementTree install
				import cElementTree as etree
				print("running with cElementTree")
			except ImportError:
					try:
					# normal ElementTree install
					import elementtree.ElementTree as etree
					print("running with ElementTree")
				except ImportError:
					print("Failed to import ElementTree from any known place")

RE: Nested Imports - CanadaGuy - Nov-07-2018

Thanks for the reply. Is try/except a better approach than using an if statement? In this case, I know exactly what statement will work under each condition so try except seems a little less direct.

RE: Nested Imports - Larz60+ - Nov-08-2018

'if' statements will not stop error events from crashing system, try/except will

RE: Nested Imports - CanadaGuy - Nov-08-2018

(Nov-08-2018, 12:19 AM)Larz60+ Wrote: 'if' statements will not stop error events from crashing system, try/except will

True. That gives me something to think about.