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Function arg tweaks

This commit is contained in:
hadley 2016-08-10 15:56:09 -05:00
parent 93a23b3f28
commit 9398e03ddf
1 changed files with 3 additions and 3 deletions
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functions.Rmd
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@ -446,7 +446,7 @@ if (y < 20) {
## Function arguments
The arguments to a function typically fall into two broad sets: one set supplies the data to compute on, and the other supplies arguments that control the details of the computation. For example:
The arguments to a function typically fall into two broad sets: one set supplies the __data__ to compute on, and the other supplies arguments that control the __details__ of the computation. For example:
* In `log()`, the data is `x`, and the detail is the `base` of the logarithm.
@ -471,12 +471,12 @@ mean_ci <- function(x, conf = 0.95) {
x <- runif(100)
mean_ci(x)
mean_ci(x, 0.99)
mean_ci(x, conf = 0.99)
```
The default value should almost always be the most common value. The few exceptions are to do with safety. For example, it makes sense for `na.rm` to default to `FALSE` because missing values are important. Even though `na.rm = TRUE` is what you usually put in your code, it's a bad idea to silently ignore missing values by default.
When you call a function, typically you can omit the names for the data arguments (because they are used so commonly). If you override the default value of a detail argument, you should use the full name:
When you call a function, you typically omit the names of the data arguments (because they are used so commonly). If you override the default value of a detail argument, you should use the full name:
```{r, eval = FALSE}
# Good