我有一个用ggplot(ggplot + geom_bar)创建的直方图,我就像这样添加了一行:
+ geom_hline(aes(yintercept = 0.05),linetype='dashed')
我想在图例中添加一个条目,表示虚线是预期值。
虽然Stack Overflow上有类似的问题,但我找不到我需要的答案......
知道该怎么做吗?
答案 0 :(得分:5)
在ggplot问题的情况下制作可重复的示例非常方便,下次应该这样做。这是答案:
ggplot(diamonds, aes(clarity, fill = cut)) + geom_bar(position = "dodge") +
# linetype has to be aes; show_guide = TRUE is important
geom_hline(aes(yintercept = 1500, linetype = "Expected value"),
show_guide = TRUE) +
# 2 means dashed
scale_linetype_manual("Title", values = 2) +
# This fixes some problems, try linetype = 1 and another legend will be ruined
guides(fill = guide_legend(override.aes = list(linetype = 0)))