DataFrame.expanding(min_periods1, centerFalse, axis0)
return 的是a Window sub-classed for the particular operation参数min_periods : int, default 1
意思是:Minimum number of observations in window required to have a value (otherwise result is NA)…
需要修改list_today里面的值,接口正常返回数据,赋值后输出了值,但是后面的蓝色小图标显示this value was evaluated upon first expanding.It may have changed sincethen. 并且渲染到页面也为空