RMarkdown - 有条件的标题（table 之前的文本标题）

Question

我有一个参数化的 R Markdown。基本上，我通过“case_id”字段过滤数据帧并输出这些过滤结果的 table。我在一个循环中呈现 RMarkdown 文档，循环遍历每个唯一 case_id。对于数组中的每个 case_id，我检查数据帧，如果它存在，我输出一个过滤的 table 显示 case_id 的结果。此处的工作示例：

RMarkdown:

---
title: "My Title"
output: 
  html_document:
params:
   case: case

---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```


## My Table

```{r warning = FALSE, echo = FALSE, fig.height=10, fig.width=6}
data <- read.csv(text="case_id,event,group,start,end,color,line.color
                       3,event_1,Project,2020-06-15,2020-10-15,#ffffff,#FF0000
                       3,event_1,Meetings,2020-07-30,2020-07-30,#ffffff,#0000ff
                       5,event_1,Meetings,2020-08-30,2020-08-30,#ffffff,#FF0000
                       5,event_1,Meetings,2020-08-30,2020-08-30,#ffffff,#FF0000
                       5,event_1,Meetings,2020-08-30,2020-08-30,#ffffff,#FF0000
                       9,event_1,Meetings,2017-01-15,2017-01-15,#ffffff,#FF0000")
data$case_id <- as.numeric(data$case_id)
if(any(params$case==data$case_id)) {
    
   #Filter PDMP by the selected case
    data.filtered <- data %>%
                        filter(params$case==case_id)
    
    data.filtered <- data.filtered %>%
      filter(!is.na(start)&!is.na(end))
    
    pdmp_numRows <- nrow(data.filtered)

    if (pdmp_numRows>0) { 

    #Print table of prescriptions
    data.filtered %>%
      arrange(start)%>%
      kable() %>%  kable_styling(bootstrap_options = "striped","condensed", font_size = 12)
      
    }
    
 }


```

这是呈现它的 R 脚本：

library(dplyr)
library(knitr)
library(rmarkdown)


#--------------------- Render RMarkdown Document ---------------------
case_array <- c(1:10)

render_data <- function(case) {
  # assuming the output format of input.Rmd is PDF
  rmarkdown::render(
    "C:/Temp/test_kable.Rmd",
    output_file = paste0('//my_directory/', 'test_cable_ex_',case, '.html'),
    params = list(case=case),
    envir = parent.frame()
  )
}

for (case in case_array) {
  render_data(case)
}

table按预期输出。问题是，当没有 table 时（当过滤数据帧的行 = 0 时），我不希望 table 标题“My Table”出现。我只想在 table 存在时显示“我的 Table”。

这就是我想要的：

这是我不想要的：

Answer 1

首先将您的 csv 加载到 data.frame，然后将标题放入一个块中，只有当存在具有所提供 ID 的案例时才会对其进行评估：

---
title: "My Title"
output: 
  html_document:
params:
   case: case

---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
data <- read.csv(text="case_id,event,group,start,end,color,line.color
                       3,event_1,Project,2020-06-15,2020-10-15,#ffffff,#FF0000
                       3,event_1,Meetings,2020-07-30,2020-07-30,#ffffff,#0000ff
                       5,event_1,Meetings,2020-08-30,2020-08-30,#ffffff,#FF0000
                       5,event_1,Meetings,2020-08-30,2020-08-30,#ffffff,#FF0000
                       5,event_1,Meetings,2020-08-30,2020-08-30,#ffffff,#FF0000
                       9,event_1,Meetings,2017-01-15,2017-01-15,#ffffff,#FF0000")
data$case_id <- as.numeric(data$case_id)
```

```{r, eval=any(params$case==data$case_id), results='asis'}
print("## My Table")
```

Answer 2

您可以通过将 table 标题包装在适当的 if 语句中来做到这一点。

   ---
    title: "My Title"
    output: 
      html_document:
    params:
       case: case
    ---

    ```{r setup, include=FALSE}
    knitr::opts_chunk$set(echo = TRUE)
    ```

    ```{r warning = FALSE, echo = FALSE, fig.height=10, fig.width=6}
    data <- read.csv(text="case_id,event,group,start,end,color,line.color
                           3,event_1,Project,2020-06-15,2020-10-15,#ffffff,#FF0000
                           3,event_1,Meetings,2020-07-30,2020-07-30,#ffffff,#0000ff
                           5,event_1,Meetings,2020-08-30,2020-08-30,#ffffff,#FF0000
                           5,event_1,Meetings,2020-08-30,2020-08-30,#ffffff,#FF0000
                           5,event_1,Meetings,2020-08-30,2020-08-30,#ffffff,#FF0000
                           9,event_1,Meetings,2017-01-15,2017-01-15,#ffffff,#FF0000")
    data$case_id <- as.numeric(data$case_id)
    param_check <- any(params$case==data$case_id)
    if (param_check) {
        
       #Filter PDMP by the selected case
        data.filtered <- data %>%
                            filter(params$case==case_id)
        
        data.filtered <- data.filtered %>%
          filter(!is.na(start)&!is.na(end))
        
        pdmp_numRows <- nrow(data.filtered)
        
    }
    ```

    `r  if (param_check) { if (pdmp_numRows > 0) {"# My Table"} }`

    ```{r warning = FALSE, echo = FALSE, fig.height=10, fig.width=6}
    if(param_check) {    
      if (pdmp_numRows>0) { 
    
        #Print table of prescriptions
            data.filtered %>%
          arrange(start)%>%
          kable() %>%  kable_styling(bootstrap_options = "striped","condensed", font_size = 12)
        
      }
      
    }
    
    
    ```

RMarkdown - 有条件的标题（table 之前的文本标题）

RMarkdown - having the title (text heading before a table) be conditional

html

r

r-markdown

kable