绘图中的次轴不适用于不同的比例

Question

如何在 plotly 中重现下图

library(dplyr)
library(ggplot2)

tibble(x =1:10, y = 1:10) %>% 
        ggplot(aes(x,y)) +
        geom_line() + 
        scale_y_continuous(sec.axis = ~.*2)

我根据这个答案here尝试了以下代码

library(dplyr)
library(plotly)

tibble(x =1:10, y = 1:10) %>% 
      mutate(y2 = y*2) %>% 
      plot_ly() %>%  
      add_lines(x =~x, y =~y) %>% 
      add_lines(x= ~x, y=~y2, 
                yaxis = "y2", color = I("transparent"), 
                hoverinfo='skip', showlegend=FALSE) %>% 
      layout(yaxis2 = list(side = "right", overlaying = "y", showgrid = FALSE), 
             margin = list(r = 50))

虽然乍一看它似乎可以工作，但它只提供了部分解决方案，因为如果我以交互方式尝试更改生成图形上主（左）y 轴的比例（通过向上或向下拖动），右轴不随图形移动（因为它仅链接到第二个不可见图形）。这当然是不可接受的，因为它不允许可靠地使用 plotly 的任何交互功能，这就是我想用它而不是 ggplot 开始的原因。

编辑：刚刚意识到，在轴之间的非线性变换的情况下，这个情节解决方案似乎根本不起作用（而 ggplot 处理得很好）。

Answer 1

您只需要设置 dtick 和 tick0 即可让 plotly 拥有与 ggplot2 相同的图形。见下文；

library(plotly)
library(dplyr)

tibble(x =1:10, y = 1:10) %>% 
  mutate(y2 = y*2) -> df1

n0 <- 4
y0 <- max(df1$y)/n0
x0 <- max(df1$x)/n0

df1 %>% 
 plot_ly(data = . , x = ~x, y = ~y,
         type = "scatter", mode = "lines", width = 800, 
         color = I("red"), name = "") %>%
  
   add_trace(x = ~x, y = ~y2, yaxis = "y2", 
             color = I("red"), name = "") %>%
  
   layout(yaxis = list(showline = FALSE, side = "left",
                       title = "", color = "red", 
                       dtick = y0, tick0 = y0, fixedrange=TRUE),
          
          yaxis2 = list(showline = FALSE, side = "right", overlaying = "y", position = 1,
                        title = "", anchor = "free", color = "blue",
                        dtick = 2*y0, tick0 = 2*y0, fixedrange=TRUE),
          
          xaxis = list(showline = FALSE, zeroline = FALSE, title = "",
                       dtick = x0, tick0 = x0),
          
          showlegend = FALSE,
          margin = list(l = 50, r = 50, b = 50, t = 50, pad = 4)
  )

^{由reprex package (v0.3.0) 于 2020 年 6 月 19 日创建}