Feeding R data to html in R markdown, where the output is a Word document

Question

I would like to automatically create a table in R Markdown, where the table is created in html, but the data comes from R. Could anyone help me with how to do this?

R data:

dat <- structure(list(rn = c("W", "M"), `[      0,     25)` = c(5L, 
0L), `[     25,     50)` = c(0L, 0L), `[     25,    100)` = c(38L, 
3L), `[     50,    100)` = c(0L, 0L), `[    100,    250)` = c(43L, 
5L), `[    100,    500)` = c(0L, 0L)), row.names = c(NA, -2L), class = c("data.table", 
"data.frame"))

   rn [      0,     25) [     25,     50) [     25,    100) [     50,    100) [    100,    250) [    100,    500)
1:  W                 5                 0                38                 0                43                 0
2:  M                 0                 0                 3                 0                 5                 0

Html code:

  <html>   
       <table border="1">
       <tr>
           <td width="150">Lower threshold</td>
           <td width="50">0</td>           
           <td width="50">25</td>
           <td width="50">50</td>
           <td width="50">100</td>
           <td width="50">250</td>       
       <tr>
           <td width="150">Upper threshold</td>
           <td width="50">25</td>
           <td width="50">50</td>
           <td width="50">100</td>
           <td width="50">250</td>
           <td width="50">500</td>     
       <tr>
           <td width="150">Category W</td>
           <td width="100" colspan="1">5</td>
           <td width="100" colspan="2">38</td>
           <td width="100" colspan="2">5</td>
       </tr>   
       <tr>
           <td width="150">Category M</td>
           <td width="100" colspan="1">0</td>
           <td width="100" colspan="2">3</td>
           <td width="100" colspan="2">5</td>
       </tr>

EDIT: Formatting

<html>
<head>
<style>
table {
  font-family: arial, sans-serif;
  border-collapse: collapse;
  width: 100%;
}

td, th {
  border: 1px solid #dddddd;
  text-align: left;
  padding: 8px;
}

tr:nth-child(even) {
  background-color: #dddddd;
}
</style>
</head>

score 1 · Accepted Answer · answered Apr 22 '22 at 09:32

One approach to create your HTML table from scratch which makes heavy use of htmltools and purrr may look like so. To make this work you have to do some data wrangling to put your data and the info needed to create your data in a tidy data format:

---
title: "HTML Table"
date: '2022-04-19'
output: html_document
---

```{r echo=FALSE}
dat <- structure(list(
  row = structure(c(
    1L, 1L, 1L, 1L, 1L, 2L, 2L,
    2L, 2L, 2L, 3L, 3L, 3L, 4L, 4L, 4L
  ), .Label = c(
    "Lower threshold",
    "Upper threshold", "Category W", "Category M"
  ), class = "factor"),
  value = c(
    0, 25, 50, 100, 250, 25, 50, 100, 250, 500, 5,
    38, 5, 0, 3, 5
  ), width = c(
    50, 50, 50, 50, 50, 50, 50, 50,
    50, 50, 100, 100, 100, 100, 100, 100
  ), colspan = c(
    NA, NA,
    NA, NA, NA, NA, NA, NA, NA, NA, 1, 2, 2, 1, 2, 2
  )
), row.names = c(
  NA,
  -16L
), class = "data.frame")
```

```{r}
head(dat)
```

```{r echo=FALSE}
make_html_table_row <- function(row, label) {
  htmltools::tagList(
    htmltools::tags$td(label, width = "150"),
    purrr::pmap(row, function(row, value, width, colspan) {
      htmltools::tags$td(value, width = width, colspan = if (!is.na(colspan)) colspan)
    })
  ) |>
    htmltools::tags$tr()
}

make_html_table <- function(x) {
  x_split <- split(x, x$row)
  purrr::imap(x_split, make_html_table_row) |>
    htmltools::tagList() |>
    htmltools::tags$table(border = "1") |>
    htmltools::tags$html()
}
```

```{r results='asis'}
make_html_table(dat)
```

DATA

Code used to create the data.

dat <- list(
  data.frame(
    row = "Lower threshold",
    value = c(0, 25, 50, 100, 250),
    width = 50,
    colspan = NA
  ),
  data.frame(
    row = "Upper threshold",
    value = c(25, 50, 100, 250, 500),
    width = 50,
    colspan = NA
  ),
  data.frame(
    row = "Category W",
    value = c(5, 38, 5),
    width = 100,
    colspan = c(1, 2, 2)
  ),
  data.frame(
    row = "Category M",
    value = c(0, 3, 5),
    width = 100,
    colspan = c(1, 2, 2)
  )
) |>
  dplyr::bind_rows()

dat$row <- factor(dat$row, levels = c("Lower threshold", "Upper threshold", "Category W", "Category M"))

Hi Stefan, thanks again, your code works great. I was trying to add some basic formatting to the table (see EDIT). I tried to implement them in the `tags$table(border = "1")` part, but without much success. Could you perhaps give me one example of how adding the formatting should work? — Tom, Apr 25 '22 at 08:57
I made a new question for my comment: https://stackoverflow.com/questions/71997074/html-formatting-in-rmarkdown — Tom, Apr 25 '22 at 09:12

Feeding R data to html in R markdown, where the output is a Word document

EDIT: Formatting

1 Answers1

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