Instance 042: Variable scope

Title:Learn how to use auto to define variables.

Program Analysis: Variable scope in python.

Python local variable global, global variable local, non-local variable nonlocal, Enclosing function locals scope_Lazy Blog-CSDN Blog

I. Problem solving ideas:

In C, auto automatically stores the type. Generally, we rarely declare variables as auto type in the program.Because variables in code blocks are of this type by default, variables of this type are stored on the stack,That is to say, such automatic variables will only be created when the program executes these code blocks, and the automatic variables will be released after the execution of the code block.auto int num = 1That is to say, only then execute this line of codeThe num in the auto variable will exist. After this line of code is executed, the auto variable will be automatically released.We know that Python does not need to declare variables, once the variable is initialized, the type and value are determined.Determines the type of the variable based on the value type.In Python, the auto keyword does not exist# import keyword## print(keyword.kwlist)# print(keyword.iskeyword('auto'))If you try to enter auto in pycharm, the editor will probably prompt you to enter autopep8, don't think this is how auto is written in pythonUse autopep8 to automatically typeset Python code to the PEP 8 specificationautopep8 is an open source command line tool that automatically formats Python code into PEP8 style.autopep8 uses the pycodestyle tool to determine which parts of the code need to be formatted, which fixes most of the typography issues reported by the pycodestyle tool.autopep8 itself is also a tool written in Python language, we can install it directly using pipWithout the auto keyword, you can use variable scope as an exampleIn python, the default local variable local global variable uses global

Second, code:

def my_global():global gg = 99print('my_global', g)n = 11def my_nonlocal():# nonlocal is generally used in closure functions, variables declared by nonlocal are in the upper-level local scope, not globally definednonlocal nn = 22my_nonlocal()print('n', n)my_global()print('g', g)

Three, running results

↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓Lazy laughter and sincerityInvite you to click below to learn and discuss together↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓