# xy.coords

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##### Extracting Plotting Structures

xy.coords is used by many functions to obtain x and y coordinates for plotting. The use of this common mechanism across all relevant Rfunctions produces a measure of consistency.

Keywords
dplot
##### Usage
xy.coords(x, y = NULL, xlab = NULL, ylab = NULL, log = NULL,
recycle = FALSE)
##### Arguments
x, y
the x and y coordinates of a set of points. Alternatively, a single argument x can be provided.
xlab, ylab
names for the x and y variables to be extracted.
log
character, "x", "y" or both, as for plot. Sets negative values to NA and gives a warning.
recycle
logical; if TRUE, recycle (rep) the shorter of x or y if their lengths differ.
##### Details

An attempt is made to interpret the arguments x and y in a way suitable for bivariate plotting (or other bivariate procedures).

If y is NULL and x is a [object Object],[object Object],[object Object],[object Object] In any other case, the x argument is coerced to a vector and returned as y component where the resulting x is just the index vector 1:n. In this case, the resulting xlab component is set to "Index".

If x (after transformation as above) inherits from class "POSIXt" it is coerced to class "POSIXct".

##### Value

• A list with the components
• xnumeric (i.e., "double") vector of abscissa values.
• ynumeric vector of the same length as x.
• xlabcharacter(1) or NULL, the label of x.
• ylabcharacter(1) or NULL, the label of y.

plot.default, lines, points and lowess are examples of functions which use this mechanism.
library(grDevices) xy.coords(stats::fft(c(1:9)), NULL) with(cars, xy.coords(dist ~ speed, NULL)\$xlab ) # = "speed" xy.coords(1:3, 1:2, recycle = TRUE) xy.coords(-2:10, NULL, log = "y") ##> warning: 3 y values <= 0 omitted ..