Python variable scope

There are four types of Python for scopes: buildin scope, global scope (module scope or file scope), high-level function scope, and local scope.

Where the Buildin scope is the Python built-in scope, which was established when Python was initialized;

The global scope is the scope of the variable directly defined in the file;

The scope of the high-level function is the scope of the local variables defined in the outer function;

Local scope is the scope of local variables defined inside the function;

In the Python language, the position where the variable is assigned is the scope in which the variable is located.

Python searches for a variable first from the local scope, finds the upper function scope, the global scope, and the Buildin scope if it is not found, and throws an exception if the lookup has no results.

Therefore, the variable assignment statement in the inner layer overrides the outer variable definition.

If you need to modify the global variables in the inner layer, then you need the global statement to declare the scope of the variable.

Python variable scope