R ggplot2 - 如何指定越界值的颜色 [英] R ggplot2 - How do I specify out of bounds values' colour

问题描述

在下面的代码生成的图中，我想改变颜色，以便所有值< 0.6与低颜色相同，而大于1的所有值都是高颜色。

正如现状一样，颜色渐变横跨整个数字范围的数据。我尝试添加限制，但是这使得所有超出界限的值与NA值相同，这不是我想要的，因为我需要缺少NA值以清楚地伸出并且看起来不像超出界限值<0.6 。

我相信，答案是oob，打破了论点，但没有成功实现它。

  library（ggplot2）
a = rnorm（17 * 17，0.733,0.21）
 qcMat = matrix（a，ncol = 17）
 qcMat [qcMat> 1] = 1 
 #qcMat包含0和1之间的值，并且一些NAs 
 
m = melt（t（qcMat））
m $ Var2 < - 其中（m，factor Var2，levels = rev（sort（unique（Var2）））））
 ggplot（m，aes（as.factor（Var1），Var2，group = Var2））+ 
 geom_tile（aes（fill = value））+ 
 geom_text（aes（fill = m $ value，label = round（m $ value，2）））+ 
 scale_fill_gradient（low =red，high =green） + 
 xlab（）+ ylab（）+ ggtitle（paste（biscuit：，biscuit_id，QC，sep =））
  

解决方案

正如你所说，你需要 oob 参数在 scale_fill_gradient 中。要限制值，您可以使用从音阶包裹中挤压（安装 ggplot2 时安装 scales ）：

  library（比例）
  

及更高版本

  scale_fill_gradient（low =red，high =green，limits = c（0.6,1），oob = squish）
  

In the plot generated by the following code I would like to alter the colours so that all values < 0.6 are the same as the "low" colour and all values greater than 1 are the "high" colour.

As is stands the colour gradient stretches across the entire numeric range of the data. I have tried adding limits but that makes all out of bounds value the same colour as NA values, which is not what I want because I need missing NA values to clearly stick out and not look the same colour as out of bounds values <0.6.

I'm convinced that the answer is with the oob, breaks arguments but have had no success getting it to work.

library(ggplot2)
a = rnorm(17*17, 0.733,0.21)
qcMat = matrix(a, ncol = 17)
qcMat[qcMat> 1] = 1
#qcMat contains values between 0 and 1 and some NAs

m = melt(t(qcMat))
m$Var2 <- with(m,factor(Var2, levels = rev(sort(unique(Var2)))))
ggplot(m, aes(as.factor(Var1), Var2, group=Var2)) +
  geom_tile(aes(fill = value)) +
  geom_text(aes(fill = m$value, label = round(m$value, 2))) +
  scale_fill_gradient(low = "red", high = "green") +
  xlab("") + ylab("") + ggtitle(paste("biscuit:", biscuit_id, "- QC", sep = " "))

解决方案

As you said youself, you want the oob argument in the scale_fill_gradient. To clamp values, you can use squish from the scales package (scales is installed when ggplot2 is installed):

library(scales)

and later

scale_fill_gradient(low = "red", high = "green", limits=c(0.6, 1), oob=squish)

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