问题
Whenever I try to plot my xts object with values passed for parameter col and lwd, it returns an error saying that the parameter col (and then lwd if I comment out col) matched multiple values. Here is what the function looks like -
data is an xts object
plot(data, lwd=2, col="red")
Installing xtsExtra seems to solve the problem, but I don't understand why.
回答1:
xts:::plot.xts specifies several parameters when constructing the axes (col, lwd, las, and mgp), but it also passes ... to the axis call. For example:
axis(1, at = xycoords$x, labels = FALSE, col = "#BBBBBB", ...)
col is already specified, so if you specify it also, it gets passed to axis via ... and now there are two col arguments specified to the axis call.
This isn't a problem with xtsExtra:::plot.xts because those parameters are removed from ... before ... is passed to the axis call.
回答2:
My solution to this to pass type='n' and then call lines:
require(quantmod)
getSymbols('CPIAUCSL',src='FRED')
xts::plot.xts(CPIAUCSL, type='n')
lines(CPIAUCSL, lwd=3, col='darkgoldenrod')
This does not require the xtsExtra package, which makes other changes to the plot and is (maybe) not being actively maintained. (At least it doesn't install via the package manager, today, on R 3.1.1.)
来源：https://stackoverflow.com/questions/16473411/plotting-xts-objects-passsing-values-for-lwd-and-col-parameters-creating-error