How to make a local variable (inside a function) global
Possible Duplicate:
Using global variables in a function other than the one that created them
I'm using functions so that my program won't be a mess but I don't know how to make a local variable into global.
Here are two methods to achieve the same thing:
Using parameters and return (recommended)
def other_function(parameter):
return parameter + 5
def main_function():
x = 10
print x
x = other_function(x)
print x
When you run main_function , you'll get the following output
>>> 10
>>> 15
Using globals (never do this)
x = 0 # The initial value of x, with global scope
def other_function():
global x
x = x + 5
def main_function():
print x # Just printing - no need to declare global yet
global x # So we can change the global x
x = 10
print x
other_function()
print x
Now you will get:
>>> 0 # Initial global value
>>> 10 # Now we've set it to 10 in `main_function()`
>>> 15 # Now we've added 5 in `other_function()`
Simply declare your variable outside any function:
globalValue = 1
def f(x):
print(globalValue + x)
If you need to assign to the global from within the function, use the global statement:
def f(x):
global globalValue
print(globalValue + x)
globalValue += 1
If you need access to the internal states of a function, you're possibly better off using a class. You can make a class instance behave like a function by making it a callable, which is done by defining __call__ :
class StatefulFunction( object ):
def __init__( self ):
self.public_value = 'foo'
def __call__( self ):
return self.public_value
>> f = StatefulFunction()
>> f()
`foo`
>> f.public_value = 'bar'
>> f()
`bar`
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