Conditional Slide Rendering in Quarto Presentations Based on Dataframe Size (RStudio)

[nerazhu]

Description

Hi everyone,

I'm working on automated reporting in RStudio using Quarto, with output to PowerPoint (pptx).
I want to conditionally render slides based on the number of observations in a dataframe.

Problem:
For example, if df_companyX has fewer than 5 observations, I want to skip rendering slide 3 entirely (not just skip the code chunk, but avoid creating an empty slide).

What I Tried:

• Using chunk options in the slide titles like {include="r nrow(df_companyX) > 5"} to conditionally include content.
• Skipping code execution when nrow(df_companyX) < 5.

However, the last approach still result in empty slides when the condition is not met. Manually deleting empty slides isn’t practical, as I’m generating over 100 reports.

Question:
Is there a way in Quarto to conditionally render (or skip) an entire slide based on a data condition, so that no empty slide is produced in the output?

Context:

• Output format: PowerPoint (pptx)
• Quarto version: 1.7.32

Any help or pointers would be appreciated, as this is for a client and manual cleanup would be a big pain.

Thank you and wishing you the best!
Luca

---
title: "Example Presentation"
format: pptx
---

```{r setup}
# example dataframe
df_companyX <- data.frame(
  x = 1:5,
  y = rnorm(5)
)
```

## Slide 1

- rendered in every presentation

## Slide 2

- rendered when nrow(df_companyX) > 5

(edited because of formatting).

[mcanouil]

In order to do that, you need to generate the whole slide markdown in your code.

Note that you should have nothing except the language between the brackets. If you want to add a label, use #| label: setup.

---
title: "Example Presentation"
format: pptx
---

```{r}
#| label: setup
#| output: asis
# example dataframe
df_companyX <- data.frame(
  x = 1:5,
  y = rnorm(5)
)
if (nrow(df_companyX) >= 5L) {
  cat("## Slide that validates condtion")
}
```

---

Could you properly format your post using code blocks for code and terminal outputs? Thanks.
If your code contains code blocks, you need to enclose it using more backticks, i.e., usually four ````.
See https://quarto.org/bug-reports.html#formatting-make-githubs-markdown-work-for-us.

[nerazhu]

Thank you for your quick response. This was exactly what I was searching for!

I edited the formatting. Thanks for the hint!

Sunny greetings!