pandas报错：A value is trying to be set on a copy of a slice from a DataFrame.

• 问题描述：

使用pandas就行复制（赋值）时出现：A value is trying to be set on a copy of a slice from a DataFrame.

• 解决方法：
  1，mydf=mydf.copy()
  2，先初始化一个格式a，再把要复制的b赋值给a。