Pass Variable On Import

user_16363 0
Viewed 43295

Let's say you have some time-consuming work to do when a module/class is first imported. This functionality is dependent on a passed in variable. It only needs to be done when the module/class is loaded. All instances of the class can then use the result.

For instance, I'm using rpy2:

import rpy2.robjects as robjects

PATH_TO_R_SOURCE = ## I need to pass this
robjects.r.source(PATH_TO_R_SOURCE, chdir = True) ## this takes time

class SomeClass:
  def __init__(self, aCurve):
    self._curve = aCurve

  def processCurve(self):
    robjects.r['someRFunc'](robjects.FloatVector(self._curve))

Am I stuck creating a module level function that I call to do the work?

import someClass
someClass.sourceRStuff(PATH_TO_R_SOURCE)
x = someClass.SomeClass([1,2,3,4])
etc...
import python
9 Answers

in any imported module you can do something like,

if ___name__!="__main__": import __main__ as mn x=mn.x

where you can use x as in the imported module, first by setting x in main, also you can do something like mn.y=55 , so in main module after import you will be able to use y variable.

user_48992630
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