相关疑难解决方法(0)

我有以下代码绘制点并在它们之间画一条线.

ggplot (data = subset(df, vowel == "O" & gender == "f"), aes (x = time, y = val, color = formant)) +
      geom_point()+
      geom_line(aes(group=interaction(formant, number)))

它产生了这个:

有没有办法按颜色/线型对负斜率与这些线的正斜率进行分组？

编辑:这是我的数据:

number <- c(1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3)
formant <- c("F2", "F2", "F2", "F2", "F2", "F2", "F3", "F3", "F3", "F3", "F3", "F3")
time <- c(50, 50, 50, 99, 99, 99, 50, 50, 50, 99, 99, 99)
val <- c(400, 500, 600, 450, 550, 650, 300, …