Python Decorator Simple Example

Example of a simple adorner:

def servlet(func):    print("into servlet")#1    print(servlet)#2    def foo():        print("into foo")#7        print(func)#8，真正的bar函数        func()#9        print("out foo")#13    print(foo)#3    print("out servlet")#4    return foo@servletdef bar():    print("in old bar")/#0    print(bar)#11    print("out old bar")#12print(bar)#5，已经被装饰器装饰了bar()#6

Execution sequence as above, execution result is as follows

into servlet<function servlet at 0x00000186A1341E18><function servlet.<locals>.foo at 0x00000186A1801E18>out servlet<function servlet.<locals>.foo at 0x00000186A1801E18>into foo<function bar at 0x00000186A1801AE8>in old bar<function servlet.<locals>.foo at 0x00000186A1801E18>out old barout fooProcess finished with exit code 0

Examples of variable-parameter adorners:

def desc(func):    print("in desc")    print(desc)    def foo(*arg1,**arg2):        print("in foo")        print(func)        x = func(*arg1,**arg2)        print("out foo")        return x    print(foo)    print("out desc")    return foo@descdef setArg1(x,y):    print("in setArg1")    print(setArg1)    print("out setArg1")    return x + y@descdef setArg2(x,y,z):    print("in setArg2")    print(setArg2)    print("out setArg2")    return x + y + zprint(setArg1)print(setArg2)x = setArg1(100,200)y = setArg2(100,200,300)print(x)print(y)

Code as above, execution results are as follows

in desc<function desc at 0x0000024DF2611E18><function desc.<locals>.foo at 0x0000024DF2AD1E18>out descin desc<function desc at 0x0000024DF2611E18><function desc.<locals>.foo at 0x0000024DF2AD1EA0>out desc<function desc.<locals>.foo at 0x0000024DF2AD1E18><function desc.<locals>.foo at 0x0000024DF2AD1EA0>in foo<function setArg1 at 0x0000024DF2AD1AE8>in setArg1<function desc.<locals>.foo at 0x0000024DF2AD1E18>out setArg1out fooin foo<function setArg2 at 0x0000024DF2AD1A60>in setArg2<function desc.<locals>.foo at 0x0000024DF2AD1EA0>out setArg2out foo300600Process finished with exit code 0

Python Decorator Simple Example