How to generate natural cubic spline in R?

If one enters:

??"spline"

... You get quite a few matches. The one in the stats functions that  
probably answers your specific questions is:

"splinefun {stats}                  R Documentation
Interpolating Splines               Description
Perform cubic (or Hermite) spline interpolation of given data points,  
returning either a list of points obtained by the interpolation or a  
function performing the interpolation."

"splinefun returns a function with formal arguments x and deriv, the  
latter defaulting to zero. This function can be used to evaluate the  
interpolating cubic spline (deriv=0), or its derivatives (deriv=1,2,3)  
at the points x, where the spline function interpolates the data  
points originally specified. This is often more useful than spline."

Perhaps you need to review from you basic intro material regarding
help.search("text")     # or
??"text"    # possibilities.

David Winsemius

On Mar 30, 2009, at 10:58 PM, minben wrote:

> Suppose I have two var x and y,now I want to fits a natural cubic
> spline in x to y,at the same time create new var containing the
> smoothed values of y. How can I get it?
>
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> and provide commented, minimal, self-contained, reproducible code.

David Winsemius, MD
Heritage Laboratories
West Hartford, CT