class TestYield:
 def gen_iterator(self):
  result_list = []
  for j in range(3):
   print(f"gen_iterator-{j}")
   result_list.append(j)
  # return在循环的外部，待变量完全生成后一次性返回
  return result_list

 def call_gen_iterator(self):
  # 执行下边这句后result_list直接是完成的结果[0,1,2]
  result_list = self.gen_iterator()
  for i in result_list:
   print(f"call_gen_iterator-{i}")

if __name__ == "__main__":
 obj = TestYield()
 obj.call_gen_iterator()

class TestYield:
 def gen_iterator(self):
  for j in range(3):
   print(f"do_something-{j}")
   # yield在for循环内部
   yield j

 def call_gen_iterator(self):
  # yield并不是直接返回[0,1,2]，执行下边这句后result_list什么值都没有
  result_list = self.gen_iterator()
  # i每请求一个数据，才会触发gen_iterator生成一个数据
  for i in result_list:
   print(f"call_gen_iterator-{i}")

if __name__ == "__main__":
 obj = TestYield()
 obj.call_gen_iterator()

class TestYield:
 def gen_iterator(self):
  for j in range(3):
   print(f"do_something-{j}")
   # yield在for循环内部
   yield j

 def gen_iterator_middle(self):
  print(f"gen_iterator_middle")
  # 返回的是迭代器的句柄，所以加一层return不影响是可以理解的
  return self.gen_iterator()

 def call_gen_iterator(self):
  # yield并不是直接返回[0,1,2]，执行下边这句后result_list什么值都没有
  result_list = self.gen_iterator_middle()
  # i每请求一个数据，才会触发gen_iterator生成一个数据
  for i in result_list:
   print(f"call_gen_iterator-{i}")

if __name__ == "__main__":
 obj = TestYield()
 obj.call_gen_iterator()