Get a List of points obtained by Interpolation in R Programming – spline() and splinefun() Function

In R programming, spline() and splinefun() function is used to create a list of points obtained by interpolation. It performs cubic spline interpolation of given data points.

Syntax:
spline(x, y, method)
and
splinefun(x, y, method)

Parameters:
x, y: represents vectors giving the points for interpolation
method: represents the type of spline interpolation to be used

To know about more optional parameters of both the functions, use below command in console:

help("spline")

Example 1:

# Coordinates
n <- 100
x <- 1:n
y <- rnorm(n)

# Output to be present as PNG file
png(file = "splineGFG.png")

# Spline() function
plot(x, y, main = "spline() function")
lines(spline(x, y))

# Saving the file
dev.off()

Output:

Example 2:

# Coordinates
n <- 100
x <- 1:n
y <- sin((x-0.5)*pi)

# Output to be present as PNG file
png(file = "splinefunGFG.png")

f <- splinefun(x, y)
curve(f(x))

# Saving the file
dev.off()

Output: