scope.md

Scope

LEGB rule

When a variable is called, Python will look for it in the below order.

• L: local Names assign in any way within a function and not declared global within that function
• E: enclosing Names in the local scope of any and all enclosing functions, from inner to outer
• G: global (module) Names assigned at the top level of a module file or declared global in a function within the file
• B: build-in (Python) Names pre-assigned in the build-in name module (open, range, SyntaxError, etc.)

# squishybears.py

name = "Pierre"

-------------------

# global
from squishybears import name

# global
name = "Wuzwuz"

def greet():
    # enclosing
    name = "Puffy"

    def hello():
        # local
        name = "Kozy"
        print('Hello', name)

    hello()

Global variables

Global variables are declared at the top (non-indented) level in a script (or imported in a module). To change a global variable's value inside a function, need to call global followed by variable name within the function. The function will then operate on the global variable instead of a local one.

# global
name = "Wuzwuz"

def greet():
    global name
    name = "Puffy"
    # now operating on global "name" variable, not a local one