[R] What does this command "~" mean?
edd at debian.org
Sun Jan 29 05:45:19 CET 2006
On 28 January 2006 at 20:12, Michael wrote:
| I am reading books and tutorials about R.
| I don't understand the following:
| plot(salary~rank, data=salary)
| plot(Ozone~date, data=airquality)
| I don't understand what does "~" here,
If all else fails, you could consult the help system via either one of
and within Emacs/ESS you even get to drop the quotes around ~. In short, ~
stands between the left and right side of a model. So what econometrics
books would call
Y = X beta + epsilon
gets written here as
Y ~ X
with the coefficient vector beta and errors epsilon being implied.
| and how can plot() have a input
| argument called "data"... I have looked it up in "plot"'s help but I could
| not find about argument "data".
The 'R Intro' manual may be of help here. In short
> plot(Ozone~Day, data=airquality)
works because it tells plot that the columns Ozone and Day are part of the
data.frame airquality. The shorter plot(Ozone~Day) would fail unless you had
attach'ed airquality. Again, the 'R Intro' manual may help.
Hell, there are no rules here - we're trying to accomplish something.
-- Thomas A. Edison
More information about the R-help