How to use local variable in a function and return it?

Question

I am trying to create a script that sets a local variable, references it from a function, and can return the manipulated value back to the main scope (or whatever it\'s call

Answer 1

#!/usr/bin/env python
chambersinreactor = 0; cardsdiscarded = 0;

def find_chamber_discard():
    chambersinreactor = 0
    cardsdiscarded = 0
    chambersinreactor += 1 
    cardsdiscarded += 1 
    return(chambersinreactor, cardsdiscarded)

#Here the globals remain unchanged by the locals.
#In python, a scope is similar to a 'namespace'
find_chamber_discard()

print chambersinreactor #prints as 0
print cardsdiscarded 

#I've modified the function to return a pair (tuple) of numbers.
#Above I ignored them. Now I'm going to assign the variables in the 
#main name space to the result of the function call.
print("=====with assignment===")
(chambersinreactor, cardsdiscarded) = find_chamber_discard()

print chambersinreactor #  now prints as 1
print cardsdiscarded 

# Here is another way that doesn't depend on returning values.
#Pass a dictionary of all the main variables into your function
#and directly access them from within the function as needed

print("=======using locals===")
def find_chamber_discard2(_locals):
    _locals['chambersinreactor'] += 1
    _locals['cardsdiscarded'] += 1
    return

find_chamber_discard2(locals())

print chambersinreactor #incremented the value, which was already 1
print cardsdiscarded