ggplot2和facet_grid：为每个图添加最大值

这可以解决问题。如果始终具有固定范围，则可以手动放置文本。

library(ggplot2)

data <- data.frame('group'=rep(c('A','B'),each=4),'hour'=rep(c(1,2,3,4),2),'value'=c(5,4,2,3,6,7,4,5))

ggplot(data,aes(x = hour, y = value)) +
    geom_line() +
    geom_point() +
    geom_text(
        aes(x, y, label=lab),
        data = data.frame(
            x=Inf,
            y=Inf,
            lab=tapply(data$value, data$group, max),
            group=unique(data$group)
        ),
        vjust="inward",
        hjust = "inward"
    ) +
    theme(aspect.ratio=1) +
    scale_x_continuous(name ="hours", limits=c(1,4)) +
    scale_y_continuous(limits=c(1,10),breaks = seq(1, 10, by = 2))+
    facet_grid( ~ group)