用 NAs 展平 dplyr 中的 tibble答案

【问题标题】：flatten a tibble in dplyr with NAs用 NAs 展平 dplyr 中的 tibble
【发布时间】：2018-07-21 22:49:37
【问题描述】：

我有以下tibble 数据，

 h <- structure(list(label = list(list(structure(list(id = 431676528L, 
    url = "https://api.github.com/repos/emergenzeHack/terremotocentro/labels/per%20sviluppatori", 
    name = "per sviluppatori", color = "d4c5f9", default = FALSE), .Names = c("id", 
"url", "name", "color", "default")), structure(list(id = 442034204L, 
    url = "https://api.github.com/repos/emergenzeHack/terremotocentro/labels/sito%20principale", 
    name = "sito principale", color = "5319e7", default = FALSE), .Names = c("id", 
"url", "name", "color", "default"))), list(structure(list(id = 442051239L, 
    url = "https://api.github.com/repos/emergenzeHack/terremotocentro/labels/mappa", 
    name = "mappa", color = "0052cc", default = FALSE), .Names = c("id", 
"url", "name", "color", "default")), structure(list(id = 431676528L, 
    url = "https://api.github.com/repos/emergenzeHack/terremotocentro/labels/per%20sviluppatori", 
    name = "per sviluppatori", color = "d4c5f9", default = FALSE), .Names = c("id", 
"url", "name", "color", "default")), structure(list(id = 442034204L, 
    url = "https://api.github.com/repos/emergenzeHack/terremotocentro/labels/sito%20principale", 
    name = "sito principale", color = "5319e7", default = FALSE), .Names = c("id", 
"url", "name", "color", "default"))), list(NA_character_)), mainId = c("216226960", 
"215647494", "242390063")), .Names = c("label", "mainId"), row.names = c(NA, 
-3L), class = c("tbl_df", "tbl", "data.frame"))

我想将标签中的值与mainId 配对，以便我可以将label 中的每个子元素与其主 ID 链接起来。我正在尝试获取带有标题的tibble：label，url，name，color，mainId。

a similar question 的解决方案可以正常工作，除非NAs 嵌套在label 的子元素中

map_df(h, flatten_dfr)

bind_rows_(x, .id) 中的错误：参数 1 必须有名称

【问题讨论】：

您希望删除第三个mainID，还是将NA 用于其他值？
@alistaire 我想要 NAs

标签： tibble tibble r dplyr flatten tibble

【解决方案1】：

您可以先过滤掉缺少label 的mainIds，然后用full_join 重新添加它们（或者如果您的mainIds 是唯一的，则只需添加bind_rows）。

library(tidyverse)

h_label_missing <- h %>% 
  filter(map_lgl(label, ~all(is.na(.)))) %>% 
  select(-label)

h %>% 
  filter(!map_lgl(label, ~all(is.na(.)))) %>% 
  mutate(label = map(label, bind_rows)) %>% 
  unnest() %>% 
  full_join(h_label_missing, by = "mainId")

# A tibble: 6 x 6
#     mainId         id url                                                                                  name             color  default
#       <chr>     <int> <chr>                                                                                <chr>            <chr>  <lgl>  
# 1 216226960 431676528 https://api.github.com/repos/emergenzeHack/terremotocentro/labels/per%20sviluppatori per sviluppatori d4c5f9 F      
# 2 216226960 442034204 https://api.github.com/repos/emergenzeHack/terremotocentro/labels/sito%20principale  sito principale  5319e7 F      
# 3 215647494 442051239 https://api.github.com/repos/emergenzeHack/terremotocentro/labels/mappa              mappa            0052cc F      
# 4 215647494 431676528 https://api.github.com/repos/emergenzeHack/terremotocentro/labels/per%20sviluppatori per sviluppatori d4c5f9 F      
# 5 215647494 442034204 https://api.github.com/repos/emergenzeHack/terremotocentro/labels/sito%20principale  sito principale  5319e7 F      
# 6 242390063        NA NA                                                                                   NA               NA     NA

【讨论】：

【解决方案2】：

这是一种将仅包含 NA_character_ 的元素替换为 NAs 的列表的方法，该列表的名称类似于第一行的第一个元素。之后，bind_rows 和unnest 将正常工作。

library(tidyverse)

nested_names <- names(pluck(h, 'label', 1, 1))

h2 <- h %>% 
    mutate(label = map(label, map_if, 
                       ~is.null(names(.x)), 
                       ~setNames(rep(list(NA), length(nested_names)), 
                                 nested_names)), 
           label = map(label, bind_rows)) %>% 
    unnest()

h2
#> # A tibble: 6 x 6
#>   mainId           id url                           name     color default
#>   <chr>         <int> <chr>                         <chr>    <chr> <lgl>  
#> 1 216226960 431676528 https://api.github.com/repos… per svi… d4c5… FALSE  
#> 2 216226960 442034204 https://api.github.com/repos… sito pr… 5319… FALSE  
#> 3 215647494 442051239 https://api.github.com/repos… mappa    0052… FALSE  
#> 4 215647494 431676528 https://api.github.com/repos… per svi… d4c5… FALSE  
#> 5 215647494 442034204 https://api.github.com/repos… sito pr… 5319… FALSE  
#> 6 242390063        NA <NA>                          <NA>     <NA>  NA

【讨论】：