如何使用Flextable根据单元格值为动态命名列添加脚注

解决方案 #

核心问题：flextable的footnote()方法对i参数的解析逻辑和bg()方法不同，当你为多列批量添加脚注时，i需要传入和目标列长度匹配的行索引列表，你之前传入公式列表的写法无法被正确识别。

你只需要修改to.table函数中脚注相关的逻辑即可，完整修改后的代码如下：

library(tidyverse) 
library(rlang)
library(flextable) # 原代码漏了该依赖加载，补充避免运行报错

a <- as_tibble(x =cbind( Year = c(2018, 2019, 2020),
                         a = 1:3,
                         b.1 = c("a", "b", "c"),
                         b.2 = c("c", "b", "a"), 
                         fac = c("This", "This","That"))) %>% 
  mutate(across(Year:a, ~as.numeric(.)),
         across(where(is.character), ~ as.factor(.)))


foo <- function(x, y, z, ...){
  y_var <- enquo(y)
  
  x %>%
    filter(Year %in% c(2019, 2020),
           ...) %>%
    mutate(!!quo_name(y_var) := factor(!!y_var,
                              levels = z,
                              ordered = TRUE)) %>%
    arrange(!!y_var)
    
}


to.table <- function(x, y, z, ...){
  y_var <- enquo(y)
  
  df.in <- foo(x=x,
               y=!!y_var,
               z= z)
  cond <- as.formula(glue::glue('~ !is.na({quo_name(y_var)})'))
 
  #Columns to evaluate
  cols.eval <- names(df.in)[startsWith(names(df.in), prefix = "b")]
  # 新增：预计算每个b列下值为c的行索引
  rows_with_c <- lapply(cols.eval, function(col) which(df.in[[col]] == "c"))
  bg_picker <- scales::col_factor(
    domain = c("a", "b", "c"),
    palette = c("green", "white", "Red3"),
    levels = c("a", "b", "c"),
    ordered = TRUE
  )
  
  
  
  flextable(df.in) %>%
    bold(i = cond,
         part = "body") %>%
    bg(j = cols.eval,
       bg = bg_picker) %>%
    footnote(j = cols.eval,
             i = rows_with_c, # 替换为预计算的行索引列表
             value = as_paragraph("This is the first footnote"),
             ref_symbols = "a",
             part = "body", inline = TRUE)

}

to.table(x=a,
         y=Year,
         z= c(2020,2018,2019),
         fac == "This")

运行后所有值为c的b.*列单元格都会正确添加脚注标识，符合需求。

内容的提问来源于stack exchange，提问作者Reed