Any variable defined outside of a function is a global variable. Its value is accessible inside of and outside of any function. Global variables are overridden by local variables if given the same name, meaning in a function, the local variable will be called rather than the global one.

Global Variable

http://pages.cs.wisc.edu/~calvin/cs110/LOCAL_GLOBAL.html#:~:text=A%20local%20variable%20is%20a,use%20them%20within%20that%20function.

Local Variable Reference Source

A variable defined inside a function and it can only be used/called within this function. Calling this variable outside of the function it is defined in will lead to an error. This is an important idea in Python, as new users are frequently confused over the scope of defined variables.

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Use the equal sign ("=") with the variable name on the left and the value on the right. 

Examples:
- car_model = "Ford Taurus"
- Total_Cost = 400
- n = 18

Note that the equal sign does not mean "equal to" in this case. It should be read as "(Variable) refers to (Value)." For example, "n refers to 18." 

Setting Variables in Python 

The traditional equal sign "=" is known as the assignment token in Python. It is used to assign values to variables. "a = b" means "b is assigned to a."

The double equal sign "==" refers to equality in an expression. So to represent "a equals b", we would write "a == b". 

= versus == in Python

A good why to represent variables and their respective assignments on paper is through the use of a reference diagram, also known as a state snapshot. It shows the respective states or assignments for each variable at a given point in time.  

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