R中的ggplot boxplot分組

Question

對於示例數據框：

   df <- structure(list(year = c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 3L, 3L, 3L, 3L, 3L, 3L, 
3L, 3L, 3L, 3L, 3L, 3L, 3L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 
4L, 4L), letter_group = c("A", "A", "A", "B", "B", "B", "C", 
"C", "C", "C", "A", "A", "A", "B", "B", "B", "C", "C", "C", "C", 
"A", "A", "A", "B", "B", "B", "C", "C", "C", "C", "C", "C", "C", 
"A", "A", "A", "B", "B", "B", "C", "C", "C", "C", "C"), value = c(2L, 
3L, 4L, 5L, 6L, 6L, 7L, 8L, 5L, 6L, 7L, 3L, 4L, 5L, 6L, 4L, 5L, 
6L, 2L, 3L, 4L, 4L, 5L, 6L, 7L, 8L, 5L, 3L, 2L, 4L, 5L, 6L, 4L, 
3L, 4L, 5L, 6L, 7L, 1L, 2L, 4L, 5L, 6L, 4L)), .Names = c("year", 
"letter_group", "value"), row.names = c(NA, -44L), class = c("tbl_df", 
"tbl", "data.frame"), spec = structure(list(cols = structure(list(
    year = structure(list(), class = c("collector_integer", "collector"
    )), letter_group = structure(list(), class = c("collector_character", 
    "collector")), value = structure(list(), class = c("collector_integer", 
    "collector"))), .Names = c("year", "letter_group", "value"
)), default = structure(list(), class = c("collector_guess", 
"collector"))), .Names = c("cols", "default"), class = "col_spec"))

我正在嘗試創建一個包含x軸年份的箱形圖 - 以及按年份分組的'字母組'...

即A，B，C為第1年，然后是小空間A，BC，第2年等等....

我有以下內容：

library(ggplot2)

p1 <- ggplot(df, aes(year, value))
p1 + geom_boxplot(aes(group=letter_group))

但這只是產生3箱圖。

有人可以幫幫我嗎？

Answer 1

@ nouse解決方案的替代方案（這是最好的解決方案）是使用分面。 但是，分面的一個好處是您還可以在x軸上獲得字母組標簽。

定義數據結構

# Load library
library(ggplot2)

# Define data frame
df <- structure(list(year = c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
                              2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 3L, 3L, 3L, 3L, 3L, 3L, 
                              3L, 3L, 3L, 3L, 3L, 3L, 3L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 
                              4L, 4L), letter_group = c("A", "A", "A", "B", "B", "B", "C", 
                                                        "C", "C", "C", "A", "A", "A", "B", "B", "B", "C", "C", "C", "C", 
                                                        "A", "A", "A", "B", "B", "B", "C", "C", "C", "C", "C", "C", "C", 
                                                        "A", "A", "A", "B", "B", "B", "C", "C", "C", "C", "C"), 
                     value = c(2L, 3L, 4L, 5L, 6L, 6L, 7L, 8L, 5L, 6L, 7L, 3L, 4L, 5L, 6L, 4L, 5L, 
                               6L, 2L, 3L, 4L, 4L, 5L, 6L, 7L, 8L, 5L, 3L, 2L, 4L, 5L, 6L, 4L, 
                               3L, 4L, 5L, 6L, 7L, 1L, 2L, 4L, 5L, 6L, 4L)), 
                .Names = c("year", "letter_group", "value"), 
                row.names = c(NA, -44L), 
                class = c("tbl_df","tbl", "data.frame"), 
                spec = structure(list(cols = structure(list( ear = structure(list(), class = c("collector_integer", "collector")), 
                                                             letter_group = structure(list(), class = c("collector_character", "collector")), 
                                                             value = structure(list(), class = c("collector_integer",  "collector"))), 
                                                       .Names = c("year", "letter_group", "value")), 
                                      default = structure(list(), class = c("collector_guess", "collector"))), 
                                 .Names = c("cols", "default"), class = "col_spec"))

繪制結果

# Plot results
g <- ggplot(df)
g <- g + geom_boxplot(aes(letter_group, value))
g <- g + facet_grid(. ~ year, switch = "x")
g <- g + theme(strip.placement = "outside",
               strip.background = element_blank(),
               panel.background = element_rect(fill = "white"),
               panel.grid.major = element_line(colour = alpha("gray50", 0.25), linetype = "dashed"))
g <- g + ylab("Value") + xlab("Year & Letter Group")
print(g)

^{由reprex包創建於2019-05-23（v0.2.1）}

Answer 2

您的問題已在很大程度上回答了這里 。

您的數據框不包含因素，因此您首先需要將分組變量轉換為因子。 然后，根據上面給出的鏈接，有兩個選項。 通過組合兩個原始因子構建一個新因子（如z-cool的答案中所示） - 但這不會在x軸上創建因子水平之間的所需空間 - 或者您需要指定一個因子來fill或者col 。 在您的情況下，解決問題的最快方法是

ggplot(df, aes(as.factor(year), value, fill=as.factor(letter_group))) + geom_boxplot()

如果您不想為您的繪圖着色，可以使用scale_fill_manual或scale_color_manual更改此scale_color_manual ，具體取決於您之前在aes的選擇：

ggplot(df, aes(as.factor(year), value, fill=as.factor(letter_group))) + geom_boxplot() +
  scale_fill_manual(values=c("white", "white", "white")) +
  theme(legend.position = "none")

Answer 3

這應該工作

library(tidyverse)
df %>% 
  mutate(year_group = paste(year, letter_group)) %>% 
  ggplot(aes(year_group, value)) +
  geom_boxplot()