高级 `data.table` 在块中运行时工作正常，但在 `knit2html` 时出错答案

【问题标题】：Advanced `data.table` working fine when run in chunk but error when `knit2html`高级 `data.table` 在块中运行时工作正常，但在 `knit2html` 时出错
【发布时间】：2021-01-12 20:44:57
【问题描述】：

我试图参考下面的链接使用data.table包来计算mape,smape,mse,rmse，它在块中运行时与下面的代码工作正常，但在@987654330时出错@。有人给我遮光吗？

## https://tysonbarrett.com/jekyll/update/2019/10/06/datatable_memory
## http://brooksandrew.github.io/simpleblog/articles/advanced-data-table
require('DescTools')
require('data.table')

setorder(seasonal_m1, index)

open.accr <- seasonal_m1[, {
  open = open
  open.Point.Forecast = open.Point.Forecast
  .SD[, .(.N, open.mape = MAPE(open, open.Point.Forecast), 
          open.smape = SMAPE(open, open.Point.Forecast), 
          open.mse = MSE(open, open.Point.Forecast), 
          open.rmse = RMSE(open, open.Point.Forecast)), 
      by={index=as_date(index)}]}, 
  by=.(Model, Period)]

错误：

Error in `[.tbl_df`(seasonal_m1, , { : 
  object 'open.Point.Forecast' not found
Calls: <Anonymous> ... withCallingHandlers -> withVisible -> eval -> eval -> [ -> [.tbl_df
Execution halted

【问题讨论】：

标签： r data.table r-markdown knitr

【解决方案1】：

seasonal_m1 <- data.table(seasonal_m1)
setorder(seasonal_m1, index)

已解决，需要将seasonal_m1 转换为data.table 格式。 https://github.com/yihui/knitr/issues/1941#issuecomment-759275616

【讨论】：