Just chiming in here...
Granted some of the help files are a bit cryptic until you get used to
them (but still much easier to understand than the Unix man pages :-)
). This sort of thing does provide a chance to learn about the power of R.
From Rolf's example, suppose that integrate() did NOT have any
additional arguments. Then, do this:
bar <- function(x) foo(x,y=pi/4)
integrate(bar, 0, 2*pi)
As an exercise to the reader :-) , write a function which takes an input
for the value of y and uses some subset of "paste, eval, do.call, parse"
etc., to build the function bar() on the fly.
Carl
<quote>
From: Rolf Turner <rolf.turner_at_xtra.co.nz>
Date: Sat, 06 Aug 2011 11:00:11 +1200
On 06/08/11 08:17, brunero liseo wrote:
> Is it possible to use the "integrate" function when it depends on a
> parameter?
> in other words can i get something like
>
> f(y) = integrate (g(x,y))?
> If not, how else can I get that?
> thanks in advance
This really boils down to ``RTFM''.
The help for "integrate" ``clearly'' ( :-) ) states that there is a
"..." argument
which consists of ``additional arguments passed to f''. So use it.
E.g.:
foo <- function(x,y){sin(x^2 + y^2)}
integrate(foo,0,2*pi,y=pi/4)
0.9314315 with absolute error < 1.5e-05
Most of the time, what you need to know is in the help. You just need to
learn to read the help *carefully* and think along the lines: ``This
*does* mean something useful and is actually expressed in a rational
albeit it cryptic manner. Given that fact, what could this *possibly*
mean?''
That will usually get you there. Then *try* what you think you gleaned
from the help using a *simple* example.
cheers,
Rolf Turner
</quote>
--
-----
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