我和malcook在他的评论中指出的情况相同:不幸的是,Thierry提供的答案在ggplot2版本0.9.3.1中无法使用。
png("figure_%d.png")
set.seed(2014)
library(ggplot2)
dataset <- data.frame(category = rep(LETTERS[1:5], 100),
x = rnorm(500, mean = rep(1:5, 100)),
y = rnorm(500, mean = rep(1:5, 100)))
dataset$fCategory <- factor(dataset$category)
subdata <- subset(dataset, category %in% c("A", "D", "E"))
ggplot(dataset, aes(x = x, y = y, colour = fCategory)) + geom_point()
ggplot(subdata, aes(x = x, y = y, colour = fCategory)) + geom_point()
这是第一个图:
和第二个数字:
我们可以看到颜色不是固定的,例如 E 从洋红色变成了蓝色。
正如
malcook在
his comment中和
hadley在
his comment中建议的那样,使用
limits
的代码可以正常工作:
ggplot(subdata, aes(x = x, y = y, colour = fCategory)) +
geom_point() +
scale_colour_discrete(drop=TRUE,
limits = levels(dataset$fCategory))
给出如下图,是正确的:
这是sessionInfo()
的输出:
R version 3.0.2 (2013-09-25)
Platform: x86_64-pc-linux-gnu (64-bit)
locale:
[1] LC_CTYPE=en_US.UTF-8 LC_NUMERIC=C
[3] LC_TIME=en_US.UTF-8 LC_COLLATE=en_US.UTF-8
[5] LC_MONETARY=en_US.UTF-8 LC_MESSAGES=en_US.UTF-8
[7] LC_PAPER=en_US.UTF-8 LC_NAME=C
[9] LC_ADDRESS=C LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C
attached base packages:
[1] methods stats graphics grDevices utils datasets base
other attached packages:
[1] ggplot2_0.9.3.1
loaded via a namespace (and not attached):
[1] colorspace_1.2-4 dichromat_2.0-0 digest_0.6.4 grid_3.0.2
[5] gtable_0.1.2 labeling_0.2 MASS_7.3-29 munsell_0.4.2
[9] plyr_1.8 proto_0.3-10 RColorBrewer_1.0-5 reshape2_1.2.2
[13] scales_0.2.3 stringr_0.6.2
fillScale <- scale_fill_manual(name = "grp",values = myColors)
以在条形图中使用它。 - pentandrous