Examples in R

The same folds, from the knitr engine.

The collapse-output filter folding output from R cells, showing that it works on what Quarto emits rather than on any one engine.

The Examples page runs Python through Jupyter. This one runs R through knitr, from the renv environment declared at the repository root.

The filter acts on the cell and cell-output elements Quarto emits, which are the same whichever engine produced them, so nothing here is configured differently.

Folding one cell

```{r}
#| output-fold: true

summary(cars)
```
Standard Output (7 lines) 
     speed           dist       
 Min.   : 4.0   Min.   :  2.00  
 1st Qu.:12.0   1st Qu.: 26.00  
 Median :15.0   Median : 36.00  
 Mean   :15.4   Mean   : 42.98  
 3rd Qu.:19.0   3rd Qu.: 56.00  
 Max.   :25.0   Max.   :120.00

The summary comes from summary-template, set once for the whole site, and its line count is measured from the output above.

A summary of your own

```{r}
#| output-fold: true
#| output-summary: "Click to view the model"

summary(lm(dist ~ speed, data = cars))
```
Click to view the model 

Call:
lm(formula = dist ~ speed, data = cars)

Residuals:
    Min      1Q  Median      3Q     Max 
-29.069  -9.525  -2.272   9.215  43.201 

Coefficients:
            Estimate Std. Error t value Pr(>|t|)    
(Intercept) -17.5791     6.7584  -2.601   0.0123 *  
speed         3.9324     0.4155   9.464 1.49e-12 ***
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

Residual standard error: 15.38 on 48 degrees of freedom
Multiple R-squared:  0.6511,    Adjusted R-squared:  0.6438 
F-statistic: 89.57 on 1 and 48 DF,  p-value: 1.49e-12

Starting open

```{r}
#| output-fold: true
#| output-open: true

head(cars, 3)
```
Standard Output (4 lines) 
  speed dist
1     4    2
2     4   10
3     7    4

Warnings and errors

```{r}
#| output-fold: true

message("A message on the error stream.")
```
Warnings and errors 
A message on the error stream.
```{r}
#| output-fold: true

as.numeric("not a number")
```
Warnings and errors 
Warning: NAs introduced by coercion
```{r}
#| output-fold: true

head(cars, 3)
```
Standard Output (5 lines) 
[1] NA
  speed dist
1     4    2
2     4   10
3     7    4

Output on the error stream is folded separately, under summaries.stderr, while the standard stream falls back to the template.

Rich output

```{r}
#| output-fold: true
#| output-summary: "The figure"

plot(cars, pch = 19, main = "Speed and stopping distance")
```
The figure

A plot is display output rather than console text, and is folded under its own type.

Source

The repository ships a short, standalone starting point you can copy: example.qmd.

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