LEGB — Variable Scope in Python

Local, Enclose, Global and Build-in

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Each programming language has its own variable scope. For python, we could simply follow the LEGB rule that includes

Local, Enclose, Global, and Built-in.

In this article, we will use a few examples to understand their feature and how to access objects of different scopes.

Local; Enclose; Global Variable

We start from this example first

There are three variables with the same name called x, which represent different scopes.

x = 'global var'
def outer():
    # y is local variable for outer(), enclose variable for inner()
    x = 'enclose var'
    def inner():
        x = 'local var'
        print('inner: {}'.format(x))
    inner()
    print('outer: {}'.format(x))
outer()
print(x))

>>>>>>>>>>>>>>>>>>>>>>>>>
inner local var
outer enclose var
global var

Any variable outside a function is a global variable, and a variable inside a function is a local variable. If there is an outer function and an inner function, then the x in the inner function is a local variable, and the x in the outer function is an enclose variable of the internal…