Python Variable Range

1, local variables, global variables

Python has 2 variables scoped to local variables, global variables.

Variable search path is: local variable, global variable

They simply mean that the value of the local variable is valid only within the local scope. The scope of global variables is global.

For example:

　　

A = 3      def  px ():    = 4    print  (a)print  (a) PX ()

Print (a)

The result of the previous segment of the code is 3 4 the A in the 3,PX function is only a local variable, which is only valid in the code block in which it resides. Can't change the value of a outside

But with global, we'll see:

A = 3def  px ():    Global  a            = 4    print  (a)print  (a) px ()print (a)

When you add global, the variable a becomes a global variable, and its scope is global. Modify it to take effect in the global scope

Python Variable Range