使用ggvis R为线图创建辅助y轴

Question

这是我到目前为止使用R中的ggvis包。

    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.)")

我无法让左Y轴代表wt比例数据。

输出：

Answer 1

我假设您希望左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.)"  )

我觉得这就是你想要的：

修改：

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