def func():
  variable = 100 
  print(variable) 
print(variable) # name 'variable' is not defined

def counter1():
  n = 0
  def compute():
    n = n + 1 # n为标量（数值，字符串，浮点数），Python程序会因为“如果内部函数有引用外部函数的同名变量或者全局变量,并且对这个变量有修改.那么python会认为它是一个局部变量,又因为函数中没有n的定义和赋值，所以报错
    # y = n + 1 # 更改为y就没事
    # return y
    return n
  return compute

variable = 300
def test_scopt():
  print(variable) # 此时调用局部变量variable并有没绑定到一个内存对象(没有定义和初始化，即没有赋值)。本质上还是遵循的LEGB法则
  variable = 200 #因为这里，前面调用过一次，所以variable就变为了局部变量
  # print(variable) # 写在下面就没问题，因为variable是新的局部变量，而不是重新被定义，却没有绑定
test_scopt()

def counter():
  n = [0]
  def compute():
    n[0] += 1 # 更改的是n里面的第一个值，不是更改n
    return n[0]
  return compute

func = counter()
func() # 1
func() # 2
func() # 3

def counter1():
  n = 0
  def compute():
    global n # 如果在局部要对全局变量修改，需要在局部也要先声明该全局变量,但此处也会报错，因为没有全局变量n
    n += 1
    return n
  return compute


# right
def counter1():
  global n
  n = 0
  def compute():
    global n
    n += 1
    return n
  return compute

def make_counter():
  count = 0
  def counter():
    nonlocal count # 使用外层非全局变量
    count += 1
    return count
  return counter

name = "lzl"

def f1():
  print(name)

def f2():
  name = "eric"
  f1()
  
f2() # 在函数未执行之前，作用域链就已经形成了，此时f1()的上一级应该name = 'lzl'

def scope_test():
  def do_local():
    spam = "local spam" # 此函数定义了另外的一个spam字符串变量，并且生命周期只在此函数内。此处的spam和外层的spam是两个变量，如果写出spam = spam + “local spam” 会报错
  def do_nonlocal():
    nonlocal spam  # 使用外层的spam变量 test spam
    spam = "nonlocal spam"
  def do_global():
    global spam
    spam = "global spam"
  spam = "test spam"
  do_local()
  print("After local assignmanent:", spam) # test spam
  do_nonlocal()
  print("After nonlocal assignment:",spam) # nonlocal spam
  do_global()
  print("After global assignment:",spam) # nonlocal spam "In global scope:",spam) # global spam