如何在 R 的绘图中按分组线图添加图例

Question

我正在尝试为plotly分组线图中的每一行添加图例，但我找不到相关文档。这是没有图例的代码(来自官方文档 https://plot.ly/r/group-by/的代码(。

library(plotly)
p <- plot_ly(
  type = 'scatter',
  x = mtcars$hp,
  y = mtcars$qsec,
  text = paste("Make: ", rownames(mtcars),
               "<br>hp: ", mtcars$hp,
               "<br>qsec: ", mtcars$qsec,
               "<br>Cyl: ", mtcars$cyl),
  hoverinfo = 'text',
  mode = 'markers',
  transforms = list(
    list(
      type = 'groupby',
      groups = mtcars$cyl,
      styles = list(
        list(target = 4, value = list(line =list(color = 'blue'))),
        list(target = 6, value = list(line =list(color = 'red'))),
        list(target = 8, value = list(line =list(color = 'black')))
      )
      )
    )
  )

Answer 1

在底部添加布局命令将layout(showlegend = TRUE)工作。 这可以通过使用 library(dplyr) 包通过管道传入来工作，如下所示：

library(plotly)
library(dplyr)
p <- plot_ly(
  type = 'scatter',
  x = mtcars$hp,
  y = mtcars$qsec,
  text = paste("Make: ", rownames(mtcars),
               "<br>hp: ", mtcars$hp,
               "<br>qsec: ", mtcars$qsec,
               "<br>Cyl: ", mtcars$cyl),
  hoverinfo = 'text',
  mode = 'markers',
  transforms = list(
    list(
      type = 'groupby',
      groups = mtcars$cyl,
      styles = list(
        list(target = 4, value = list(line =list(color = 'blue'))),
        list(target = 6, value = list(line =list(color = 'red'))),
        list(target = 8, value = list(line =list(color = 'black')))
      )
      )
    )
  ) %>%
layout(showlegend = TRUE)