Any way to set knitr::kable() as global option for all tables in a qmd file?

[jeweljohnsonj]

Is there any way to set knitr::kable() as the default global option way of showing tables in a rendered file?

[jjallaire]

Here is one way to do it:

```{r}
#| include: false
knit_print.data.frame = function(x, ...) {
  res = paste(c("", "", knitr::kable(x)), collapse = "\n")
  knitr::asis_output(res)
}

registerS3method(
  "knit_print", "data.frame", knit_print.data.frame,
  envir = asNamespace("knitr")
)
```

```{r}
mtcars
```

That's the low-level way, the printr package also implements this by default:

```{r}
#| include: false
library(printr)
```

```{r}
mtcars
```

[mcanouil]

Indeed, I did not find them as well, just checking since related to the question ^^

[cderv]

render is a knitr option so it should be available even within Quarto but this is an advanced option, and not all functions are working for render. The printr package is heping with that by defining method wrapping function (like printr:::knit_print.data.frame wrapping knitr::kable() so that it can be used as a render function.

There are several way to do what you need above. But first let's answer the other question : df_print is different as this is really a R Markdown feature supported using a chunk option. There is no equivalent option in Quarto.

However, you can recreate the feature for your document. One can just use what is shown in the R Markdown Cookbook - the render function just needs to be resulting in what knitr expects.

For paged table this would be this function: (which is used internaly by rmarkdown for the df_print feature.

paged_print <- function(x, options) {
  knitr::asis_output(
    rmarkdown:::paged_table_html(x, options = attr(
      x,
      "options"
    )),
    meta = list(dependencies = rmarkdown::html_dependency_pagedtable())
  )
}

Then you could register it in a document so that it is applied by default for any data.frame printing.

registerS3method(
  "knit_print", "data.frame", paged_print,
  envir = asNamespace("knitr")
)

or use it on chunk basis where you need to print a data.frame in a single value chunk.

```{r, render = paged_print}
iris
```

A df_print chunk option can also be simulated this way using a option hook

knitr::opts_hooks$set(df_print = function(options) {
  if (options$df_print == "paged") {
    options$render = paged_print
  }
  options
})

this will allow something like

```{r, df_print = "paged"}
iris
```

```{r}
iris
```

• First table will be shown as paged table
• Second table will be show as usual data.frame

This would work for R output only. So I don't know if we want to make this internal to Quarto. If we do add paged table feature, then it will be differently.

I'll think more about this, but I believe we could include such feature in the printr package or another place.

Hope the above helps already achieve what you need.

[mcanouil]

Thanks for this detailed answer!

My take on the subject: I'd rather have/keep something general in Quarto and use S3 R methods or knitr hooks, if/when needed.

[cderv]

I'd rather have/keep something general in Quarto and use S3 R methods or knitr hooks, if/when needed.

I agree with that. Maybe not the right place but I throw the idea in printr (yihui/printr#41) we'll think about it.

[jeweljohnsonj]

Thank you so much for the answer!

[cderv]

For using with R, there is now a df-print option you can set in YAML: https://quarto.org/docs/computations/r.html#data-frames

So you can now set kable as default printing option.

[jeweljohnsonj]

Thanks for adding the feature.