What are the rules for local and global variables in Python?
If a variable is defined outside function then it is implicitly global. If variable is assigned new value inside the function means it is local. If we want to make it global we need to explicitly define it as global. Variable referenced inside the function are implicit global. Following code snippet will explain further the difference
#!/usr/bin/python
# Filename: variable_localglobal.py
def fun1(a):
print 'a:', a
a= 33;
print 'local a: ', a
a = 100
fun1(a)
print 'a outside fun1:', a
def fun2():
global b
print 'b: ', b
b = 33
print 'global b:', b
b =100
fun2()
print 'b outside fun2', b
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Output
$ python variable_localglobal.py
a: 100
local a: 33
a outside fun1: 100
b :100
global b: 33
b outside fun2: 33
