R 在GGPLATE中将突出的点放在前面

通过将 colored颜色 映射到条件并指定手动色标，可以使Things变得更简单:

ggplot(df, aes(t, y)) +
geom_point(aes(colour = month == 4)) +
scale_colour_manual(values = c("grey", "red")) +
labs(colour = "Month") +
theme_minimal()

但是你可能想把突出显示的点放在前面，所以你需要把绘图分成两个geom_point，以确保突出显示的点画在灰色点的后面(即顶部):

ggplot(df, aes(t, y)) +
  geom_point(data = df[df$month != 4, ], aes(colour = month == 4)) +
  geom_point(data = df[df$month == 4, ], aes(colour = month == 4)) +
  scale_colour_manual(values = c("grey", "red")) +
  labs(colour = "Month") +
  theme_minimal()

你可能想要一个更好的图例，所以你可以做一些事情，比如构造一个带有高亮显示条件的factor变量，并将其映射到color:

df$highlight <- factor(df$month == 4,
                       levels = c(T, F),
                       labels = c("April", "Other"))

ggplot(df, aes(t, y)) +
  geom_point(data = df[df$highlight == "Other", ], aes(colour = highlight)) +
  geom_point(data = df[df$highlight == "April", ], aes(colour = highlight)) +
  scale_colour_manual(values = c("grey", "red")) +
  labs(colour = "Month") +
  theme_minimal()

但由于传说的顺序就是情节的顺序，所以Other在传说中排在第一位，看起来很奇怪.可以通过指定色标的分隔符和值来更正它:

ggplot(df, aes(t, y)) +
  geom_point(data = df[df$highlight == "Other", ], aes(colour = highlight)) +
  geom_point(data = df[df$highlight == "April", ], aes(colour = highlight)) +
  scale_colour_manual(breaks = c("April", "Other"),
                      values = c("red", "grey")) +
  labs(colour = "Month") +
  theme_minimal()