xy.unique.x {sfsmisc}

Uniqify (X,Y) Values using Weights

Description

Given smoother data (x_i, y_i) and maybe weights w_i, with multiple x_i, use the unique x values, replacing the y's by their (weighted) mean and updating the weights accordingly.

Usage

xy.unique.x(x, y, w, fun.mean = mean, ...)

Arguments

x, y

numeric vectors of same length. Alternatively, x can be a ‘xy’ like structure, see xy.coords.

w

numeric vector of non-negative weights – or missing which corresponds to all weights equal.

fun.mean

the mean function to use.

...

optional arguments all passed to unique.

Value

Numeric matrix with three columns, named x, y and w with unique x values and corresponding y and weights w.

Author(s)

Martin Maechler, 8 Mar 1993.

See Also

e.g., smooth.spline uses something like this internally.

Examples

## simple example:
x <- c(1,1,2,4,3,1)
y <- 1:6
rbind(x, y)
xy.unique.x(x, y)
#   x y w
# 1 1 3 3
# 2 2 3 1
# 3 4 4 1
# 4 3 5 1
xy.unique.x(x, y, fromLast = TRUE)