[英]R: ggplot color bar graph by sign? Green = positive, Red = negative
[英]xyplot time series with positive values in green, negative in red, in R
當使用type =“l”時,你只有一個“線”,它只是一種顏色,所以你可能會選擇顏色點:
set.seed(0); require(zoo); require(lattice)
vals <- zoo(cumsum(rnorm(100)))
png()
xyplot(vals, type=c("l","p"), col=c("red", "green")[1+( vals>0)], grid=T)
dev.off()
我找到了一個解決方案,由現在谷歌的家伙Sundar Dorai-Rag提出了類似的要求(為0和0以上的封閉區域着色,他為此獲得X的交叉值的方法是反轉結果approx
)如下所示: http : //r.789695.n4.nabble.com/shading-under-the-lines-in-a-lattice-xyplot-td793875.html 。 我沒有給封閉區域着色,而是給多邊形的邊框賦予了所需的顏色,並使內部“透明”:
lpolygon <- function (x, y = NULL, border = NULL, col = NULL, ...) {
require(grid, TRUE)
xy <- xy.coords(x, y)
x <- xy$x
y <- xy$y
gp <- list(...)
if (!is.null(border)) gp$col <- border
if (!is.null(col)) gp$fill <- col
gp <- do.call("gpar", gp)
grid.polygon(x, y, gp = gp, default.units = "native")
}
find.zero <- function(x, y) {
n <- length(y)
yy <- c(0, y)
wy <- which(yy[-1] * yy[-n - 1] < 0)
if(!length(wy)) return(NULL)
xout <- sapply(wy, function(i) {
n <- length(x)
ii <- c(i - 1, i)
approx(y[ii], x[ii], 0)$y
})
xout
}
trellis.par.set(theme = col.whitebg())
png();
xyplot(vals, panel = function(x,y, ...) {
x.zero <- find.zero(x, y)
y.zero <- y > 0
yy <- c(y[y.zero], rep(0, length(x.zero)))
xx <- c(x[y.zero], x.zero)
ord <- order(xx)
xx <- xx[ord]
xx <- c(xx[1], xx, xx[length(xx)])
yy <- c(0, yy[ord], 0)
lpolygon(xx, yy, col="transparent", border = "green")
yy <- c(y[!y.zero], rep(0, length(x.zero)))
xx <- c(x[!y.zero], x.zero)
ord <- order(xx)
xx <- xx[ord]
xx <- c(xx[1], xx, xx[length(xx)])
yy <- c(0, yy[ord], 0)
lpolygon(xx, yy, col = "transparent", border = "red")
panel.abline(h = 0) ;panel.grid(v=-1, h=-1 )
}); dev.off()
我嘗試為此編寫一個自定義面板函數,它將在給定值上打破一條線
panel.breakline <- function(x,y,breakat=0,col.line,upper.col="red",lower.col="green",...){
f <- approxfun(x,y)
ff <- function(x) f(x)-breakat
psign <- sign(y-breakat)
breaks <- which(diff(psign) != 0)
interp <- sapply(breaks, function(i) uniroot(ff,c(x[i], x[i+1]))$root)
starts <- c(1,breaks+1)
ends <- c(breaks, length(x))
Map(function(start,end,left,right) {
x <- x[start:end]
y <- y[start:end]
col <- ifelse(y[1]>breakat,upper.col,lower.col)
panel.xyplot(c(left, x, right) ,c(breakat,y,breakat), col.line=col,...)
}, starts, ends, c(NA,interp), c(interp,NA))
}
你可以跑
library(zoo)
library(lattice)
set.seed(0)
zz<-zoo(cumsum(rnorm(100)))
xyplot(zz, grid=T, panel.groups=panel.breakline)
您也可以更改斷點或顏色
xyplot(zz, grid=T, panel.groups=panel.breakline,
breakat=2, upper.col="blue", lower.col="orange")
如果一個人沒有點,那么我會堅持繪圖(而不是格子)並使用剪輯,就像在這里的一個答案中一樣: 根據值繪制帶有條件顏色的折線圖
dat<- zoo(cumsum(rnorm(100)))
plot(dat, col="red")
clip(0,length(dat),0,max(dat) )
lines(dat, col="green")
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