具有做空功能的下单代码

版权声明：猪小哥 https://blog.csdn.net/food_for_thought/article/details/82751675

最开始的代码是这样的：

  # 空仓 开多
  if margin_info == [] and signal == 1:      
  # 空仓 开空
  if margin_info == [] and signal == -1:
  # 多头 平仓
  if margin_info != [] and signal == 0:
  # 空头 平仓
  if margin_info != [] and signal == 0:
  # 多头 平仓 开空
  if margin_info != [] and signal == -1:
  # 空头 平仓 开多
  if margin_info != [] and signal == 1:

左看右看还是不严谨，比如最后一个情况里面，当 signal 变为 1 的时候之前必定有一个 0 的信号，那么后面两种情况就是可有可无了。
另外，第三种情况与第四种情况完全是一样的，完全起了冲突，所以经过改进后，目前的版本是这样的：

    # 判断是否持仓
    if margin_info == []:  # 空仓
        if signal == 1:
        elif signal == -1:
    elif margin_info != []:  # 持仓
        if margin_info[2] > 0 and signal == 0:
        elif margin_info[2] < 0 and signal == 0:
        elif margin_info[2] > 0 and signal == -1:
        elif margin_info[2] < 0 and signal == 1: