Last data update: 2014.03.03
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R: Produce regular grid matrix.
Produce regular grid matrix.
Description
Produce the grid used by persp , contour, etc, as
an N x 2 matrix.
This is really outdated by expand.grid() nowadays.
Usage
xy.grid(x, y)
Arguments
x,y |
any vectors of same mode.
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Value
a 2-column matrix of “points” for each combination of x and
y , i.e. with length(x) * length(y) rows.
Author(s)
Martin Maechler, 26 Oct 1994.
See Also
expand.grid which didn't exist when
xy.grid was first devised.
Examples
plot(xy.grid(1:7, 10*(0:4)))
x <- 1:3 ; y <- 10*(0:4)
xyg <- xy.grid(x,y)
## Compare with expand.grid() :
m2 <- as.matrix(expand.grid(y,x)[, 2:1])
dimnames(m2) <- NULL
stopifnot(identical(xyg, m2))
Results
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