Any idea of using R inline code control chunk option "include"?

[JinTonique]

Description

I would like to control if the specific chunk is included in my output file by using ifelse() function of R.

Here is an example:

I defined something previously:

apple_is_square <- TRUE

Then, I don't want the following chunk included in my output file since apple_is_square <- TRUE. I did:

#| label: I love my round apple
#| include: `r ifelse(apple_is_square, paste("false"), paste("true"))`

tbl <- data.frame(v1 = c("a","b","c"), v2 = c(1,2,3))
tbl

Apparently, it does not work in this way, quarto said:

Warning messages:
1: In value[[3L]](cond) : Failed to parse chunk options in body:
Error in parse(text = code, keep.source = FALSE): <text>:1:26: unexpected symbol
1: alist( label: Production share
                             ^

2: In opts$engine <- unlist(strsplit(rmdChunkOpts, split = "(\\s|,)+"))[[1]] :
  Coercing LHS to a list

Question: Is there any way that I can choose to include the chunk according to the value of apple_is_square?

[mcanouil]

Could you share a small self-contained "working" (reproducible) example to work with, i.e., a complete Quarto document or a Git repository? Thanks.

This being said, see https://quarto.org/docs/computations/r.html#chunk-options (at the end of the linked section).

You can share a Quarto document using the following syntax, i.e., using more backticks than you have in your document (usually four ````).

````qmd
---
title: "Reproducible Quarto Document"
format: html
---

This is a reproducible Quarto document using `format: html`.
It is written in Markdown and contains embedded R code.
When you run the code, it will produce a plot.

```{r}
plot(cars)
```

The end.
````

[cscheid]

Question: Is there any way that I can choose to include the chunk according to the value of apple_is_square?

Not currently. The fundamental reason is that quarto needs to support both knitr and jupyter engines, and this is not a feature that's currently supported in jupyter.

[cderv]

#| include: `r ifelse(apple_is_square, paste("false"), paste("true"))`

You can't use inline knitr R code inside a YAML option value field. That is not a syntax that will work. Reason is simple: We need to parse the YAML before any of inline evaluation happens.

Have a look at how chunk options are written for R chunks evaluated with knit engines. https://quarto.org/docs/computations/r.html#chunk-options

FWIW there is a specific feature for engine: knitr only that is using !expr in a YAML field to have R expression evaluated at yaml parsing time

---
title: "Reproducible Quarto Document"
format: html
---

```{r}
apple_is_square <- TRUE
```

Then, I don't want the following chunk included in my output file since `apple_is_square <- TRUE.` 

```{r}
#| label: I love my round apple
#| include: !expr isFALSE(apple_is_square)
tbl <- data.frame(v1 = c("a","b","c"), v2 = c(1,2,3))
tbl
```

Reminder: this works only with knitr engine as this is a knitr feature directly (not working with engine: jupyter)