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This article will explain in detail what the scope of variables in python is, and the content of the article is of high quality, so the editor will share it with you for reference. I hope you will have some understanding of the relevant knowledge after reading this article.

Today, we will learn the scope of python and record the learning process. You are welcome to share with us.

Create a new python file named py3_scope.py, and write the operation code in this file:

# variable scope # Local local variable # Enclosing closed function variable, common in closures # Global global variable # Built-in built-in module # python find a variable quasi-obey LEGB rule # priority from L-> E-> Gmurb search # define global variable x = 'global x variables # define function Y is a local variable # valid def test (): y = 'local y' print (y) # call local variable print (x) # call global variable test () # error will be reported if you print y directly Because it is a local variable # print (y) # print global variable xprint (x) # use the keyword global to change the local variable within the function to global def test (): global x x = 'local x' print (x) # call local variable # call function test () # local x # print global variable xprint (x) # local x # the parameters in the function are local variables: def test (z): print (z) # tone Use the local variable test ('local z') # if you print z directly, you will get an error Because it is a local variable # print (z) # closed function variable def outer (): X = 'outer x' def inner (): X = 'inner x' print (x)

Inner () print (x) # call function outer () # inner x#outer x # according to LEGB rule # call function outer () # first perform x printing in inner () and then print outer () x next we comment out the x variable def outer () in inner: X = 'outer x' def inner (): # x = 'inner x' print (x)

The result of inner () print (x) # calling function outer () # outer x#outer x # is that after printing two times of outer x # calling function outer (), first execute inner () # to find that there is no local variable. According to the LEGB rule, look for the variable in the closure function # the value of x in output outer () # continue to call the value of x in outer (), and print out outer x # directly. Then modify the variable of x in inner () to nonlocal# scope to the scope of closure function. Do not use global global modifier # prevent affecting global scope def outer (): X = 'outer x' def inner (): nonlocal x x = 'inner x' print (x)

Inner () print (x) # call function outer () # inner x#inner x # built-in module variable # first import the built-in module import builtins# to view functions and other information in the built-in module print (dir (builtins)) # define a function min () def min (): pass# here take the min () function to obtain the minimum value as an example # m = min (# print (m)) # according to the LEGB rules of the variable scope Will first go to Local to find # so there will be an error. We need to pay special attention to what the scope of variables in python is. I hope the above content can be helpful to you and learn more knowledge. If you think the article is good, you can share it for more people to see.

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