如何链接图例迹线以进行图例和颜色选择？

凯文·阿森诺

问题

我移植了一些ggplot/ggvis阴谋plotly的shiny应用。关于跟踪的链接，我遇到了一个问题。我希望能够通过group图例显示/隐藏轨迹，图例在相关数据帧之间共享。

最小的工作实例

# load libraries
library(dplyr)
library(plotly)
library(viridis)

# contrived data to represent actual data points
df1 <- data.frame(x = rnorm(100),
                  y = rnorm(100),
                  group = rep(c("G1", "G2", "G3", "G4"), 25))

# contrived data to represent theoretical relationship
df2 <- data.frame(x = c(rep(-2, 4), rep(2, 4)),
                  y = c(seq(1.9, 1, -0.3), seq(-1, -1.9, -0.3)),
                  group = rep(c("G1", "G2", "G3", "G4"), 2))

# create plot with scatter and line traces
df1 %>%
  plot_ly(x = x,
          y = y,
          color = group,
          colors = viridis(n_distinct(group)),
          mode = "markers") %>%
  add_trace(x = x,
            y = y,
            color = group,
            colors = viridis(n_distinct(group)),
            mode = "lines",
            data = df2)

到目前为止的尝试

我的在线搜索，尤其是阅读密谋的文档并没有带我走远。

我可以添加showlegend = FALSE到第二条痕迹。这确实可以解决挑战，但是，我仍然要根据group值显示/隐藏该跟踪。

可能的解决方案

基于的体系结构plotly，似乎如果我可以将散布图和线条每条放置到一条迹线上，group那么我将获得所需的行为。但是，跟踪似乎只能有一个“模式”，这就是为什么我采用了我的方法的原因。

如果我继续前进，我想我应该以某种方式捕获图例的“单击时”事件并显示/隐藏group痕迹...但是我不确定如何从此开始。

回顾后代的历史

自从首次提出此问题以来ggplot2，plotly在此期间以及随后的时间里发生了一些变化。在当前版本（4.7.1）中，有一个参数legendgroup可以解决问题。

懒码

请原谅在优雅编码上的最小工作量，但是，对MWE的扩展展示了按组显示/隐藏迹线的能力。

df1_G1 <- df1 %>% filter(group == "G1")
df2_G1 <- df2 %>% filter(group == "G1")
df1_G2 <- df1 %>% filter(group == "G2")
df2_G2 <- df2 %>% filter(group == "G2")
df1_G3 <- df1 %>% filter(group == "G3")
df2_G3 <- df2 %>% filter(group == "G3")
df1_G4 <- df1 %>% filter(group == "G4")
df2_G4 <- df2 %>% filter(group == "G4")

plot_ly(type = "scatter", mode = "markers") %>%
  add_trace(df1_G1, x = df1_G1$x, y = df1_G1$y, color = I("red"),
            legendgroup = "G1", name = "G1 - scatter") %>%
  add_trace(df2_G1, x = df2_G1$x, y = df2_G1$y, color = I("red"),
            legendgroup = "G1", name = "G1 - line", mode = "lines") %>%
  add_trace(df1_G2, x = df1_G2$x, y = df1_G2$y, color = I("green"), 
            legendgroup = "G2", name = "G2 - scatter") %>%
  add_trace(df2_G2, x = df2_G2$x, y = df2_G2$y, color = I("green"),
            legendgroup = "G2", name = "G2 - line", mode = "lines") %>%
  add_trace(df1_G3, x = df1_G3$x, y = df1_G3$y, color = I("blue"),
            legendgroup = "G3", name = "G3 - scatter") %>%
  add_trace(df2_G3, x = df2_G3$x, y = df2_G3$y, color = I("blue"),
            legendgroup = "G3", name = "G3 - line", mode = "lines") %>%
  add_trace(df1_G4, x = df1_G4$x, y = df1_G4$y, color = I("orange"), 
            legendgroup = "G4", name = "G4 - scatter") %>%
  add_trace(df2_G4, x = df2_G4$x, y = df2_G4$y, color = I("orange"), 
            legendgroup = "G4", name = "G4 - line", mode = "lines")