我有一个RMarkdown脚本，如果我手动运行块，一次运行一个或者使用“Run All”，它可以正常工作。但是当我尝试使用knitr生成HTML或PDF时，我得到了一个错误：Error in select(responses, starts_with("Q1 ") & !contains("None")) %>% : could not find function "%>%"
实际的整行内容如下：
cols <- select(responses, starts_with("Q1 ") & !contains("None") ) %>% colnames()
我正在处理一项调查中的数据，其中很多问题都是“选择尽可能多的应用”类型的问题，并且有一个开放式的“以上都不是”选项。此时，我正在抽出我想要的列（所有的Q1响应，但不是Q10或Q11响应，而不是开放式响应），所以我可以使用pivot_longer()并总结响应。我得到一个所需的确切列名列表，然后计算值。
但是当我尝试使用knitr()时，它在%>%上犹豫了。

processing file: 02_Survey2020_report.Rmd
  |....                                                                  |   6%
  ordinary text without R code

  |.........                                                             |  12%
label: setup (with options) 
List of 1
 $ include: logi FALSE

  |.............                                                         |  19%
  ordinary text without R code

  |..................                                                    |  25%
label: demographics gender

Quitting from lines 28-46 (02_Survey2020_report.Rmd) 
Error in select(responses, starts_with("Q1 ") & !contains("None")) %>%  : 
  could not find function "%>%"
Calls: <Anonymous> ... handle -> withCallingHandlers -> withVisible -> eval -> eval
Execution halted

一个简化的可重复的例子得到了同样的结果，我运行了下面的程序，得到了我所期望的结果，一个整洁的表格，上面有每个答案被选中的次数：

example <- data.frame("id" = c(009,008,007,006,005,004,003,002,001,010), "Q3_Red" = c("","","","Red","","","","Red","Red","Red"), "Q3_Blue" = c("","","","","","Blue","Blue","Blue","",""),
  "Q3_Green" = c("","Green","Green","","","","","Green","",""), "Q3_Purple" = c("","Purple","","","Purple","","Purple","","Purple","Purple"), 
  "Q3_None of the above" = c(009,008,"Verbose explanation that I don't want to count." ,006,005,004,003,002,"Another verbose entry.",010)
)

cols <- select(example, starts_with("Q3") & !contains("None") ) %>%  colnames()

example %>%
  pivot_longer(cols = all_of(cols), 
               values_to = "response") %>%  
  filter(response != "") %>%   
  count(response)

但是当我使用ctrlshiftk输出文档时，我得到了同样的错误：

processing file: 00a_reproducible_examples.Rmd

Quitting from lines 9-25 (00a_reproducible_examples.Rmd) 
Error in select(example, starts_with("Q3") & !contains("None")) %>% colnames() : 
  could not find function "%>%"
Calls: <Anonymous> ... handle -> withCallingHandlers -> withVisible -> eval -> eval
Execution halted

为什么编织者在烟斗前犹豫不决？