R levelplot中的3个不同颜色区域

尝试绘制此矩阵，使负值为红色，0为蓝色，正值为绿色

m <- matrix(c(0,0,-1,-2,0,0,1,0,1,3,3,3,-3,0,0,2),nrow = 4)

levelplot(m,at=c(-3,0,3),col.regions=c("red","blue","green"),xlab = xlab.a, ylab="", colorkey = FALSE, panel = function(...) {
  panel.fill(col = "blue")
  panel.levelplot(...)
})

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m
m这里有一种使用布尔比较的通用方法：

levelplot((m>=0) + (m > 0),at=c(-0.1, 0:2),col.regions=c("red","blue","green"), xlab = "", ylab="", colorkey = FALSE, panel = function(...) {
  panel.fill(col = "blue")
  panel.levelplot(...)
})

levelplot((m>=0) + (m > 0),at=c(-0.1, 0:2),col.regions=c("red","blue","green"), xlab = "", ylab="", colorkey = FALSE, panel = function(...) {
  panel.fill(col = "blue")
  panel.levelplot(...)
})