r - 使用 ggvis R 为线图创建辅助 y 轴

Question

这就是我到目前为止在 R 中使用 ggvis 包的内容。

    mtcars %>% ggvis(x = ~disp) %>% 
    layer_lines(y = ~wt, stroke := "red") %>%
    layer_lines(y = ~mpg) %>%
    add_axis("y", orient = "left", title = "Weight (lb/1000)") %>%
    add_axis("y", orient = "right", title= "Miles/(US) gallon") %>%
    add_axis("x", title = "Displacement (cu.in.)")

我无法用左 Y 轴来表示 wt 比例数据。

这输出:

Answer 1

我假设您想要将左 y 轴(即 wt)除以 1000:

library(dplyr) #you need this library
mtcars  %>% mutate(wt_scaled=wt/1000)  %>% ggvis(x = ~disp) %>% #use mutate from dplyr to add scaled wt
  layer_lines(y = ~wt_scaled, stroke := "red") %>% #use new column
  add_axis("y", orient = "left", title = "Weight (lb/1000)" ,title_offset = 50) %>% #fix left axis label
  scale_numeric("y", domain = c(0, 0.006), nice = FALSE) %>% #align the ticks as good as possible
  add_axis("y", 'ympg' , orient = "right", title= "Miles/(US) gallon" , grid=F ) %>% #remove right y axis grid and name axis
  layer_lines( prop('y' , ~mpg,  scale='ympg') ) %>% #use scale to show layer_lines which axis it should use
  add_axis("x", title = "Displacement (cu.in.)"  )

我认为这就是你想要的:



编辑 :

如果你只是想在左 y 轴上绘制 wt(不是很清楚)，那么做 mutate(wt_scaled=wt/1) (或删除 mutate)并将域更改为 domain = c(1.5, 5.5)