标签：out == gre cal port col 完成 com int
在 if/else 语句中我们返回 greet 和 welcome，而不是 greet() 和 welcome()。为什么那样？这是因为当你把一对小括号放在后面，这个函数就会执行；然而如果你不放括号在它后面，那它可以被到处传递，并且可以赋值给别的变量而不去执行它。
def hi(name="yasoob"): def greet(): return "now you are in the greet() function" def welcome(): return "now you are in the welcome() function" if name == "yasoob": return greet else: return welcome a = hi() print(a) #outputs: <function greet at 0x7f2143c01500> #上面清晰地展示了`a`现在指向到hi()函数中的greet()函数 #现在试试这个 print(a()) #outputs: now you are in the greet() function
用函数decorator装饰function_requiring_decoration函数
import time def decorator(func): def decorator_function(): localtime = time.asctime(time.localtime(time.time())) print(‘before decorator running,time is‘, localtime) func() localtime = time.asctime(time.localtime(time.time())) print(‘after decorator running,time is ‘, localtime) #必须返回函数名，不带括号 return decorator_function def function_requiring_decoration(): a, b = 5, 3 time.sleep(1) print("The result is ", a + b) function__decoration = decorator(function_requiring_decoration) if __name__=="__main__": function__decoration()
以上代码的简写
import time def decorator(func): def decorator_function(): localtime = time.asctime(time.localtime(time.time())) print(‘before decorator running,time is‘, localtime) func() localtime = time.asctime(time.localtime(time.time())) print(‘after decorator running,time is ‘, localtime) #fanhuihans,bujiakuohao return decorator_function @decorator def function_requiring_decoration(): a, b = 5, 3 time.sleep(1) print("The result is ", a + b) if __name__=="__main__": function_requiring_decoration()
结果
before decorator running,time is Wed Jan 20 20:07:03 2021 The result is 8 after decorator running,time is Wed Jan 20 20:07:04 2021
import time class Decorator(object): def __init__(self, func): self.func = func def call(self): localtime = time.asctime(time.localtime(time.time())) print (‘before decorator running,time is‘,localtime) self.func() #run add function localtime = time.asctime(time.localtime(time.time())) print (‘after decorator running,time is ‘,localtime) @Decorator def add(): a,b=5,3 time.sleep(1) print ("The result is ",a+b) if __name__=="__main__": add.call()
结果，如上代码就完成了一个类装饰器的功能，给运行的函数添加了时间日志
before decorator running,time is Wed Jan 20 19:58:41 2021 The result is 8 after decorator running,time is Wed Jan 20 19:58:42 2021
标签：out == gre cal port col 完成 com int
原文地址：https://www.cnblogs.com/AntonioSu/p/14304832.html
