一切皆对象，那是我的对象

def hi(name="yasoob"):
  return "hi " + name
print(hi())
# output: 'hi yasoob'
# 我们甚可以将一个函数赋值给⼀个变量，如
greet = hi
# 我们这没有在使小括号，因为我们并不是在调⽤hi函数
# 是在将它放在greet变量里头。我们尝试运行下这个
print(greet())
# output: 'hi yasoob'
# 如果我们删掉旧的hi函数，看看会发什么！
del hi
print(hi())
#outputs: NameError
print(greet())
#outputs: 'hi yasoob'
Python进阶
一切皆对象 33
在函数中定义函数
在函数中定义函

def hi(name="yasoob"):
  print("now you are inside the hi() function")
def greet():
  return "now you are in the greet() function"
def welcome():
  return "now you are in the welcome() function"
print(greet())
print(welcome())
print("now you are back in the hi() function")
hi()
#output:now you are inside the hi() function
# now you are in the greet() function
# now you are in the welcome() function
# now you are back in the hi() function
# 上⾯展示了⽆论何时你调⽤hi(), greet()和welcome()将会同时被调⽤。
# 然后greet()和welcome()函数在hi()函数之外是不能访问的，⽐如：
greet()
#outputs: NameError: name 'greet' is not defined

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

def hi():
  return "hi yasoob!"
def doSomethingBeforeHi(func):
  print("I am doing some boring work before executing hi()")
  print(func())
doSomethingBeforeHi(hi)

#outputs:I am doing some boring work before executing hi()
# hi yasoob!