Shiny within Rmarkdown not rendering within loop - r

Question

I would like to render Shiny tabs (and other Shiny features) within an Rmarkdown document. Specifically, I'd like to display a table in each tab, generated with a loop.
We can add {.tabset} tag after a header and subsequent lower level headers will be separate tabs. I tried to make use of this by using cat() and the header level and a unique name at each loop for the tab name. That creates the tabs fine. Also, a table is created within each tab when I call the function with arguments separately.
However, when looping through the function, the tables are not being generated on each tab. In the final tab is output
<shiny.render.function> for each loop.
I know if I was generating a table in Rmarkdown without Shiny, I'd print each table within each loop. However, there's no similar function for printing rendered Shiny objects.
---
output: html_document
runtime: shiny
---
## Tables Work {.tabset}
{r works, results='asis'}
# Function to generate a numbered tab and table within that tab
tbl_display_func <- function(tab_number, df){
cat('### Results', tab_number,' \n\n')
DT::renderDataTable({
DT::datatable(
head(df)
)
})
}
# Works fine to call the function separately
tbl_display_func(1, cars)
tbl_display_func(2, iris)
Tables Don't Work {.tabset}
However, when I loop through the function, tables do not display.
{r do-not-work, results='asis'}
# Does not work here. Generates tabs, then list of <shiny.render.function> in tab 2
purrr::map2(
.x = list(1,2),
.y = list(cars, iris),
.f = tbl_display_func
)
I tried to create the tables as renderTableOutput output, as I might if creating multiple widgets just in shiny, and then calling those within a function, but this didn't help
Tables Don't Work {.tabset}
{r generate-tables-then-print, results='asis'}
# Function just to generate table
tbl_func <- function(df){
DT::renderDataTable({
DT::datatable(
head(df)
)
})
}
# Store rendered table as output
tbl_func_output <- purrr::map(
.x = list(cars, iris),
.f = tbl_func
)
# Loop through each tab and table
display_func <- function(tab_number){
cat('### Results', tab_number,' \n\n')
tbl_func_output[[tab_number]]
}
purrr::map(
.x = 1:2,
.f = display_func
)
How might I loop through and create a table at each tab?

Answer 1

You need to do this
---
output: html_document
runtime: shiny
---
```{r}
do.call(tabsetPanel,
mapply(y = list(cars, iris), x = list(1,2), function(x, y) {
tabPanel(
paste0("Results", x), DT::renderDataTable({DT::datatable(head(y))})
)
}, SIMPLIFY = FALSE)
)
```
return of purrr::map2 is a list, not shiny.tag object. I don't think there is a way to have .tabset work with cat and DT::datatable together. You would choose only flexdashboard or shiny. Here I used shiny syntax.