这是一个可能的解决方案,可以使绘图代码更清晰,更符合 ggplot2 的设计精神。代价是您的数据需要重新排列一下。我还使用了一些额外的代码来动态生成颜色值的命名字符向量。感谢@John Colby 的gg_color_hue()
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数据现在是“长格式”,所有 x 值和 y 值在两列中。此外,还有两个分组因素,将绘制线条的语义与着色线条和点的语义分开:
col_group line_group date total
Mary Adjuster 2012-01-01 10
Mary Adjuster 2012-02-01 15
Bob Adjuster 2012-03-01 25
Bob Adjuster 2012-04-01 15
Mary Adjuster 2012-05-01 20
Paid Paid 2012-01-01 5
Paid Paid 2012-02-01 5
Paid Paid 2012-03-01 10
Paid Paid 2012-04-01 10
Paid Paid 2012-05-01 15
dat <- data.frame(col_group=c("Mary","Mary","Bob", "Bob", "Mary",
"Paid","Paid","Paid","Paid","Paid"),
line_group=c("Adjuster","Adjuster","Adjuster","Adjuster","Adjuster",
"Paid","Paid","Paid","Paid","Paid"),
date=as.Date(c("2012-1-1","2012-2-1","2012-3-1","2012-4-1","2012-5-1",
"2012-1-1","2012-2-1","2012-3-1","2012-4-1","2012-5-1")),
total=c(10,15,25,15,20,
5, 5, 10,10,15))
# Color generating function found here:
# http://stackoverflow.com/questions/8197559/emulate-ggplot2-default-color-palette
gg_color_hue <- function(n) {
hues = seq(15, 375, length=n+1)
hcl(h=hues, l=65, c=100)[1:n]
}
# Dynamically generate default color values, but have Paid="black".
adj_names = sort(setdiff(unique(dat$col_group), "Paid"))
values = gg_color_hue(length(adj_names))
names(values) = adj_names
values = c(values, c(Paid="black"))
library(ggplot2)
plot1 <- ggplot(dat, aes(x=date, y=total, colour=col_group)) +
geom_line(aes(group=line_group), size=1.2) +
geom_point(size=2.8) +
scale_colour_manual(values=values)
ggsave("plot1.png", plot=plot1, width=6, height=4.5, dpi=120)