根據因子級別重新格式化標簽/保留ggplot2::facet_wrap()中多因子構面的順序

我希望基于兩個因素對圖形進行構面，使用兩個構面因素值的組合重命名構面，但根據原始因素中的水平保留構面的順序。

資料看起來像這樣：

library(tidyverse)

set.seed(100)

tmp.d <- data.frame(
  sector = factor(rep(c("B","A"),c(6,3)), levels = c("B","A")),
  subsector = factor(rep(c("a","b","c"), each = 3), levels = c("c","b","a")),
  year = factor(rep(2020:2022,3)),
  value = sample(8:15,9, replace = TRUE)
)

#> tmp.d
#  sector subsector year value
#1      B         a 2020     9
#2      B         a 2021    14
#3      B         a 2022    13
#4      B         b 2020    15
#5      B         b 2021    10
#6      B         b 2022     8
#7      A         c 2020     9
#8      A         c 2021    13
#9      A         c 2022    11

這是按部門和子部門繪制和分面的...

ggplot(tmp.d, aes(x = year, y = value, group = 1))  
  geom_path() 
  facet_wrap(facets = list("sector","subsector"))

...看起來像這樣：

請注意，構面保持由“部門”和“子部門”的因子水平設定的順序。這是可取的。

但是，我不想在單獨的行上列出扇區和子扇區，而是希望分面標簽讀取“[扇區]：[子扇區]”，如“B：b”。

嘗試1：

向 tmp.d 添加一個幫助列，其中包含構面標簽。

tmp.d <- tmp.d %>% mutate(label = factor(paste0(sector, ": ", subsector)))

ggplot(tmp.d, aes(x = year, y = value, group = 1))  
  geom_path() 
  facet_wrap(facets = list("label"))

產生：

Here, the facet labels are correct, but I've lost the order from the sector/subsector factor levels.

Attempt 2:

I think the answer may lay in a custom as_labeller function or perhaps even changing setting for an existing labeller like label_value which has a multi_line = [bool] attribute that controls whether the facet values appear on a single line or mulitple lines. Other versions of the label_ family have another attribute sep = which I beleive controls how the values are seperated in on the same line. Presumably, the combination of ...multi_line = FALSE, sep = ": "... might format the label and preserve the desired order.

The labeller is applied in the call to facet_wrap().

ggplot(tmp.d, aes(x = year, y = value, group = 1))  
  geom_path() 
  facet_wrap(facets = list("sector","subsector"), labeller = [the labeller function])

Setting the labeller to an existing labeller function without changing default settings (see below) yields the same output as my original attempt above.

...
facet_wrap(facets = list("sector","subsector"), labeller = label_value)
...

Attempting to change the attribute values for label_value like so...

...
facet_wrap(facets = list("sector","subsector"), labeller = label_value(multi_line = FALSE))
...

... does not work because the label_value function requires a label value that I do not know how to provide. Passing the facet factors as names or as character strings (either as a list or vector) does not appear to work. The examples I found in the documentation or elsewhere use facet_grid instead of facet_wrap, and the labels is provided as a formula like ~sector subsector which I assume is treated like a grid/matrix where sectors are columns and subsectors are rows. In my case, most (but not necessarily all) combinations of sector/subsector will be unique (i.e., Sectors A and B do not share subsectors).

Question Summary

Is there a simple way to acheive my objectives (restated for convenience):

• facet on two factor variables (facet_wrap, not facet_grid)
• 根據因子水平保留構面順序
• 將分面標簽重新格式化為單行，扇區和子扇區由冒號分隔

謝謝，

uj5u.com熱心網友回復：

哇，這比我預期的要復雜得多......一種解決方案是將它們組合到不同的領域：

tmp.d |> 
  arrange(sector, subsector) |>          # arrange by factor levels
  mutate(
    facet = 
      paste0(sector, ": ", subsector) |>    
      fct_inorder(ordered = TRUE)        # use that order for the new field
  ) |> 
  ggplot(aes(x = year, y = value, group = 1))  
  geom_path() 
  facet_wrap(facets = ~facet)            # here

如果“，”是可以接受的，這也有效：

ggplot(tmp.d, aes(x = year, y = value, group = 1))  
  geom_path() 
  facet_wrap(
    facets = sector~subsector, 
    labeller = 
      labeller(                  # here
        sector = label_value,    #
        subsector = label_value, #
        .multi_line = FALSE      #
      )
  )

可以做類似的事情，用purrr::partial()它代替默認值，但你又得到一個逗號。我認為值得在他們的 github 頁面上創建一個問題以向函式添加sep引數label_*()

...  
  facet_wrap(
    facets = sector~subsector, 
    labeller = purrr::partial(label_value, multi_line = FALSE)
  )

uj5u.com熱心網友回復：

更新：同時 yake84 已經完成了答案：要自動化，只需fct_inorder..在使用后添加arrange：

tmp.d %>% 
  arrange(sector, subsector) %>% 
  mutate(my_label = paste(sector,subsector, sep=":") %>% 
           fct_inorder(ordered = TRUE)) %>% 
  ggplot(aes(x = year, y = value, group = 1))  
  geom_path() 
  facet_wrap( ~ my_label)

第一個答案： 只需將您的標簽轉換為嘗試 1 以考慮并定義級別：

library(tidyverse)

tmp.d %>% 
  mutate(my_label = paste(sector,subsector, sep=":")) %>% 
  mutate(my_label = factor(my_label, levels = c("B:b", "B:a", "A:c"))) %>% 
  ggplot(aes(x = year, y = value, group = 1))  
  geom_path() 
  facet_wrap( ~ my_label)

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