# Passing information between steppables¶

When you work with more than one steppable (and it is a good idea to work with several steppables each of which has well defined purpose) you may sometimes need to acces/change member variable of one steppable inside the code of another steppable. If you are seasoned Python programmer, you can easily find workaround. However, we have added a convenience function to SteppableBasePy class that makes accessing content of one steppable from another module very easy and, let’s say, elegant. Here is an example (see also Demos/CompuCellPythonTutorial/SteppableCommunication):

class SteppableCommunicationSteppable(SteppableBasePy):
def __init__(self, _simulator, _frequency=1):
SteppableBasePy.__init__(self, _simulator, _frequency)

def step(self, mcs):
extraSteppable = self.getSteppableByClassName('ExtraSteppable')
print 'extraSteppable.sharedParameter=', extraSteppable.sharedParameter

class ExtraSteppable(SteppableBasePy):
def __init__(self, _simulator, _frequency=1):
SteppableBasePy.__init__(self, _simulator, _frequency)
self.sharedParameter = 25

def step(self, mcs):
print "ExtraSteppable: This function is called every 1 MCS"


In the SteppableCommunicationSteppable class, inside step function we fetch (using class name) another ExtraSteppble steppable. Once we have access to object of type ExtraSteppble we can access/change parameters of this steppable.

Remark: This approach will work fine if you create only one steppable object for each steppable class. In case you create two objects of the same steppable class, the presented method fails. However, most, if not all, CC3D simulations rely on an unwritten rule - one steppable object for each steppable class.