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

Question

我尝试参考以下链接使用 data.table 包来计算 mape、smape、mse、rmse，它工作正常当运行在块中时下面的代码但在 knit2html 时变成错误。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

Answer 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

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

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

Advanced `data.table` working fine when run in chunk but error when `knit2html`

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