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A variable is only available from inside the region it is created. This is called scope.
A variable created inside a function belongs to the local scope of that function, and can only be used inside that function.
A variable created inside a function is available inside that function:
def myfunc():
x = 300 print(x)
myfunc()As explained in the example above, the variable x is not available outside the function, but it is available for any function inside the function:
The local variable can be accessed from a function within the function:
def myfunc():
x = 300 def myinnerfunc():
print(x)
myinnerfunc()
myfunc()A variable created in the main body of the Python code is a global variable and belongs to the global scope.
Global variables are available from within any scope, global and local.A variable created outside of a function is global and can be used by anyone:
x = 300 def myfunc():
print(x)
myfunc()
print(x)If you operate with the same variable name inside and outside of a function, Python will treat them as two separate variables, one available in the global scope (outside the function) and one available in the local scope (inside the function):
The function will print the local x, and then the code will print the global x
x = 300 def myfunc():
x = 200 print(x)
myfunc()
print(x)If you need to create a global variable, but are stuck in the local scope, you can use the global keyword.
The global keyword makes the variable global.If you use the global keyword, the variable belongs to the global scope:
def myfunc():
global x x = 300 myfunc()
print(x)
Also, use the global keyword if you want to make a change to a global variable inside a function.To change the value of a global variable inside a function, refer to the variable by using the global keyword:
x = 300 def myfunc():
global x x = 200 myfunc()
print(x)The nonlocal keyword is used to work with variables inside nested functions. The nonlocal keyword makes the variable belong to the outer function.
If you use the nonlocal keyword, the variable will belong to the outer function:
def myfunc1():
x = "Jane"
def myfunc2():
nonlocal x x = "hello"
myfunc2()
return x print(myfunc1())Python follows the LEGB rule when looking up variable names, and searches for them in this order: L
ocal - Inside the current function EFormula
nclosing - Inside enclosing functions (from inner to outer)G
Formula
lobal - At the top level of the moduleB
Formula
uilt - in - In Python's built - in namespacex = "global"
def outer():
x = "enclosing"
def inner():
x = "local"
print("Inner:", x)
inner()
print("Outer:", x)
outer()
print("Global:", x)