43 lines
908 B
Plaintext
43 lines
908 B
Plaintext
|
# Evaluate and echo different lines
|
||
|
|
|
||
|
|
For demonstration purposes, we may want to show some source code in the output,
|
||
|
|
but really evaluate different code in the background.
|
||
|
|
|
||
|
|
```{r}
|
||
|
|
hook_source <- knit_hooks$get('source')
|
||
|
|
knit_hooks$set(source = function(x, options) {
|
||
|
|
res <- hook_source(x, options)
|
||
|
|
gsub("(^|\n)#'#' ", '\\1', res)
|
||
|
|
})
|
||
|
|
```
|
||
|
|
The trick is to mask the source code in special comments (e.g. `#'#'`), and
|
||
|
|
remove the comment markers later. Of course, you have to guarantee these markers
|
||
|
|
are unique.
|
||
|
|
|
||
|
|
```{r test, echo=-3}
|
||
|
|
x <- 2
|
||
|
|
## 1/sqrt(2 * pi) * exp(-x^2/2)
|
||
|
|
dnorm(x)
|
||
|
|
```
|
||
|
|
|
||
|
|
```{r sdf}
|
||
|
|
|
||
|
|
|
||
|
|
dfdfd
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
```
|
||
|
|
|
||
|
|
We used `echo=-3` to remove the 3rd expression from the source code, and
|
||
|
|
`gsub()` to strip `#'#'` off.
|
||
|
|
|
||
|
|
This is completely hack. Use with care.
|
||
|
|
|
||
|
|
Example code:
|
||
|
|
|
||
|
|
```{r}
|
||
|
|
## Example code:
|
||
|
|
paggregate(argent[, 2:5], by = list(Transect = argent$Transect, Season = argent$Season), FUN = sum)
|
||
|
|
```
|