# predict.bSpline

##### Evaluate a Spline at New Values of x

The `predict`

methods for the classes that inherit from the
virtual classes `bSpline`

and `polySpline`

are used to
evaluate the spline or its derivatives. The `plot`

method for a
spline object first evaluates `predict`

with the `x`

argument missing, then plots the resulting `xyVector`

with
`type = "l"`

.

- Keywords
- models

##### Usage

```
# S3 method for bSpline
predict(object, x, nseg = 50, deriv = 0, …)
# S3 method for nbSpline
predict(object, x, nseg = 50, deriv = 0, …)
# S3 method for pbSpline
predict(object, x, nseg = 50, deriv = 0, …)
# S3 method for npolySpline
predict(object, x, nseg = 50, deriv = 0, …)
# S3 method for ppolySpline
predict(object, x, nseg = 50, deriv = 0, …)
```

##### Arguments

- object
An object that inherits from the

`bSpline`

or the`polySpline`

class.- x
A numeric vector of

`x`

values at which to evaluate the spline. If this argument is missing a suitable set of`x`

values is generated as a sequence of`nseq`

segments spanning the range of the knots.- nseg
A positive integer giving the number of segments in a set of equally-spaced

`x`

values spanning the range of the knots in`object`

. This value is only used if`x`

is missing.- deriv
An integer between 0 and

`splineOrder(object) - 1`

specifying the derivative to evaluate.- …
further arguments passed to or from other methods.

##### Value

an `xyVector`

with components

the supplied or inferred numeric vector of `x`

values

the value of the spline (or its `deriv`

'th derivative)
at the `x`

vector

##### See Also

##### Examples

`library(splines)`

```
# NOT RUN {
require(graphics); require(stats)
ispl <- interpSpline( weight ~ height, women )
opar <- par(mfrow = c(2, 2), las = 1)
plot(predict(ispl, nseg = 201), # plots over the range of the knots
main = "Original data with interpolating spline", type = "l",
xlab = "height", ylab = "weight")
points(women$height, women$weight, col = 4)
plot(predict(ispl, nseg = 201, deriv = 1),
main = "First derivative of interpolating spline", type = "l",
xlab = "height", ylab = "weight")
plot(predict(ispl, nseg = 201, deriv = 2),
main = "Second derivative of interpolating spline", type = "l",
xlab = "height", ylab = "weight")
plot(predict(ispl, nseg = 401, deriv = 3),
main = "Third derivative of interpolating spline", type = "l",
xlab = "height", ylab = "weight")
par(opar)
# }
```

*Documentation reproduced from package splines, version 3.6.0, License: Part of R 3.6.0*