如何在绘图中跨子图对齐分组的箱线图

Question

我正在尝试使用plotly对箱形图进行子图绘制，以使相同颜色的框在x轴上彼此对齐。但是，当我使用boxmode = group分开它们时：

library(plotly)
library(tidyverse)

df <- data.frame(
  w = rep(1:3, times = 2, each = 60),
  x = rep(c("A", "B", "C"), times = 20),
  y = rep(c("D", "E", "F"), each = 20),
  z = rnorm(120)
)

p <- function(val) {
  filter(df, w == val) %>% 
    plot_ly(x = ~x, y = ~z, color = ~y, type = "box") %>% 
    layout(boxmode = "group")
} 

subplot(lapply(unique(df$w), p), nrows = 3, shareX = TRUE)

使用ggplot时不会发生这种情况：

(ggp <- ggplot(df, aes(x = x, y = z, color = y)) +
  geom_boxplot() +
  facet_wrap(. ~ w, nrow = 3))

但是如果我尝试将此图传递给ggplotly()，则会再次发生：

ggplotly(ggp) %>% 
  layout(boxmode = "group")

移除boxmode = "group"会使不同颜色的盒子相互堆叠，甚至更糟！我尝试使用alignmentgroup和offsetgroup进行一些更改，但它们似乎覆盖了boxmode参数，并导致所有内容再次堆叠。我还能做些其他什么来生成一个交互式图，以使每个框保持在各自的通道内？

here也有类似的问题，但我认为这不能解决我的问题。

Answer 1

习惯了ggplot2的感觉很尴尬，但是确实有效。技巧是将单个组的箱线图添加为单独的迹线，并设置offsetgroup。试试这个：

library(plotly)
library(tidyverse)

df <- data.frame(
  w = rep(1:3, times = 2, each = 60),
  x = rep(c("A", "B", "C"), times = 20),
  y = rep(c("D", "E", "F"), each = 20),
  z = rnorm(120)
)

p <- function(val) {
  df <- filter(df, w == val)
  # 1. Step by step
  # plot_ly(x = ~x, y = ~z, color = ~y) %>% 
  #   #purrr::reduce(unique(df$y), ~ add_trace(.y, data = filter(df, y == .x), type = "box", offsetgroup = .x))
  #   add_trace(data = filter(df, y == "D"), type = "box", offsetgroup = "D") %>%
  #   add_trace(data = filter(df, y == "E"), type = "box", offsetgroup = "E") %>%
  #   add_trace(data = filter(df, y == "F"), type = "box", offsetgroup = "F")

  # 2. using purrr::reduce
  purrr::reduce(unique(df$y), function(.x, .y) {
    add_trace(.x, data = filter(df, y == .y), type = "box", 
              offsetgroup = .y)
    }, .init = plot_ly(x = ~x, y = ~z, color = ~y))
} 

subplot(lapply(unique(df$w), p), nrows = 3, shareX = TRUE) %>% 
  layout(boxmode = "group")

给我这个情节：