如何在 dplyr 中展平小标题？答案

【问题标题】：How to flatten a tibble in dplyr?如何在 dplyr 中展平小标题？
【发布时间】：2018-02-11 17:22:29
【问题描述】：

我有以下：

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")))), mainId = c("216226960", 
"215647494")), class = c("tbl_df", "tbl", "data.frame"), row.names = c(NA, 
-2L), .Names = c("label", "mainId")) -> dt

# A tibble: 2 x 2
  label      mainId   
  <list>     <chr>    
1 <list [2]> 216226960
2 <list [3]> 215647494

我想将label 中的值与mainId 配对（这样我就可以将label 中的每个子元素与其主ID 链接起来）。因此，我试图得到一个带有标题的小标题： label,url,name,color,mainId

我想我会使用flatten_dfr() 之类的东西，但我不知道要保留mainId，主要是因为我不确定flatten_dfr(.id='') 的参数应该如何工作。

例如

dt %>% flatten_dfr(.id= 'mainId')

bind_rows_(x, .id) 中的错误：参数 1 必须有名称

什么是参数 1？我猜它是.x，但我对这个不寻常的命名感到困惑。此外，在小标题中不推荐使用行名，因此我对函数查找什么样的名称感到非常困惑（列名？行名？）。

更新：

这是traceback()的输出

> traceback()
13: stop(list(message = "Argument 1 must have names", call = bind_rows_(x, 
        .id), cppstack = list(file = "", line = -1L, stack = c("1   dplyr.so                            0x000000010a9ce464 _ZN4Rcpp9exceptionC2EPKcb + 276", 
    "2   dplyr.so                            0x000000010a9ce2a0 _ZN4Rcpp4stopERKNSt3__112basic_stringIcNS0_11char_traitsIcEENS0_9allocatorIcEEEE + 48", 
    "3   dplyr.so                            0x000000010a9e5ae6 _ZN5dplyr11bad_pos_argIPKcEEviT_ + 918", 
    "4   dplyr.so                            0x000000010a9fd43a _Z11rbind__implN4Rcpp6VectorILi19ENS_15PreserveStorageEEERKN5dplyr12SymbolStringE + 4634", 
    "5   dplyr.so                            0x000000010a9ffcce _Z10bind_rows_N4Rcpp6VectorILi19ENS_15PreserveStorageEEEP7SEXPREC + 286", 
    "6   dplyr.so                            0x000000010a9c28bc _dplyr_bind_rows_ + 140", 
    "7   libR.dylib                          0x0000000101201b90 R_doDotCall + 64", 
    "8   libR.dylib                          0x0000000101203db3 do_dotcall + 355", 
    "9   libR.dylib                          0x0000000101232249 Rf_eval + 1657", 
    "10  libR.dylib                          0x0000000101244a40 do_begin + 656", 
    "11  libR.dylib                          0x0000000101231f78 Rf_eval + 936", 
    "12  libR.dylib                          0x00000001012428e2 R_execClosure + 898", 
    "13  libR.dylib                          0x00000001012320f6 Rf_eval + 1318", 
    "14  libR.dylib                          0x0000000101244a40 do_begin + 656", 
    "15  libR.dylib                          0x0000000101231f78 Rf_eval + 936", 
    "16  libR.dylib                          0x00000001012428e2 R_execClosure + 898", 
    "17  libR.dylib                          0x00000001012320f6 Rf_eval + 1318", 
    "18  libR.dylib                          0x0000000101244a40 do_begin + 656", 
    "19  libR.dylib                          0x0000000101231f78 Rf_eval + 936", 
    "20  libR.dylib                          0x00000001012428e2 R_execClosure + 898", 
    "21  libR.dylib                          0x00000001012320f6 Rf_eval + 1318", 
    "22  libR.dylib                          0x00000001012428e2 R_execClosure + 898", 
    "23  libR.dylib                          0x0000000101236384 bcEval + 16148", 
    "24  libR.dylib                          0x0000000101231e11 Rf_eval + 577", 
    "25  libR.dylib                          0x0000000101240949 forcePromise + 169", 
    "26  libR.dylib                          0x0000000101232071 Rf_eval + 1185", 
    "27  libR.dylib                          0x0000000101246761 do_withVisible + 49", 
    "28  libR.dylib                          0x0000000101281e00 do_internal + 336", 
    "29  libR.dylib                          0x0000000101236959 bcEval + 17641", 
    "30  libR.dylib                          0x0000000101231e11 Rf_eval + 577", 
    "31  libR.dylib                          0x00000001012428e2 R_execClosure + 898", 
    "32  libR.dylib                          0x0000000101236384 bcEval + 16148", 
    "33  libR.dylib                          0x0000000101231e11 Rf_eval + 577", 
    "34  libR.dylib                          0x00000001012428e2 R_execClosure + 898", 
    "35  libR.dylib                          0x00000001012320f6 Rf_eval + 1318", 
    "36  libR.dylib                          0x00000001012428e2 R_execClosure + 898", 
    "37  libR.dylib                          0x00000001012320f6 Rf_eval + 1318", 
    "38  libR.dylib                          0x00000001012460fe do_eval + 1534", 
    "39  libR.dylib                          0x00000001012367ac bcEval + 17212", 
    "40  libR.dylib                          0x0000000101231e11 Rf_eval + 577", 
    "41  libR.dylib                          0x00000001012428e2 R_execClosure + 898", 
    "42  libR.dylib                          0x0000000101236384 bcEval + 16148", 
    "43  libR.dylib                          0x0000000101231e11 Rf_eval + 577", 
    "44  libR.dylib                          0x0000000101240949 forcePromise + 169", 
    "45  libR.dylib                          0x0000000101232071 Rf_eval + 1185", 
    "46  libR.dylib                          0x0000000101246761 do_withVisible + 49", 
    "47  libR.dylib                          0x0000000101281e00 do_internal + 336", 
    "48  libR.dylib                          0x0000000101236959 bcEval + 17641", 
    "49  libR.dylib                          0x0000000101231e11 Rf_eval + 577", 
    "50  libR.dylib                          0x00000001012428e2 R_execClosure + 898", 
    "51  libR.dylib                          0x0000000101236384 bcEval + 16148", 
    "52  libR.dylib                          0x0000000101231e11 Rf_eval + 577", 
    "53  libR.dylib                          0x00000001012428e2 R_execClosure + 898", 
    "54  libR.dylib                          0x00000001012320f6 Rf_eval + 1318", 
    "55  libR.dylib                          0x00000001012729b8 Rf_ReplIteration + 904", 
    "56  libR.dylib                          0x0000000101273eaf run_Rmainloop + 207", 
    "57  rsession                            0x000000010084e259 _ZN7rstudio1r7session12runEmbeddedRERKNS_4core8FilePathES5_bb7SA_TYPERKNS1_9CallbacksEPNS1_17InternalCallbacksE + 425", 
    "58  rsession                            0x000000010082d25c _ZN7rstudio1r7session3runERKNS1_8ROptionsERKNS1_10RCallbacksE + 3164", 
    "59  rsession                            0x0000000100108603 main + 28963", 
    "60  rsession                            0x0000000100003264 start + 52", 
    "61  ???                                 0x000000000000000b 0x0 + 11"
    ))))
12: .Call(`_dplyr_bind_rows_`, dots, id)
11: bind_rows_(x, .id)
10: dplyr::bind_rows(res, .id = .id)
9: flatten_dfr(., .id = "mainId")
8: function_list[[k]](value)
7: withVisible(function_list[[k]](value))
6: freduce(value, `_function_list`)
5: `_fseq`(`_lhs`)
4: eval(quote(`_fseq`(`_lhs`)), env, env)
3: eval(quote(`_fseq`(`_lhs`)), env, env)
2: withVisible(eval(quote(`_fseq`(`_lhs`)), env, env))
1: dt %>% flatten_dfr(.id = "mainId")

更新 2：

到目前为止的解决方案可以解决我最初提供的示例，但无法处理NA。例如：

h <- structure(list(label = list(list(NA_character_)), mainId = "242390063"), .Names = c("label", 
"mainId"), row.names = c(NA, -1L), class = c("tbl_df", "tbl", 
"data.frame"))

map_df(h, flatten_dfr)

bind_rows_(x, .id) 中的错误：参数 1 必须有名称

我很抱歉在我的原始示例中没有包含NA，但也许有人可以详细说明他的原始答案来解决这个问题？

【问题讨论】：

你不能用traceback()检查评估树吗？
@42- 我已将输出附加到 OP

标签： r dplyr

【解决方案1】：

首先将label列中的数据转换为tibbles，然后使用unnest提取嵌套label列中的信息。

library(tidyverse)

dt %>% 
  mutate(label = map(label, bind_rows)) %>% 
  unnest()

# A tibble: 5 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

【讨论】：

我非常喜欢您的解决方案，但它不能处理 label 中的 NULL 元素。但是，我理解这是因为我提供了一个糟糕的代表。

【解决方案2】：

我们可以将每个列表元素转换为列表列中的一个小标题，然后使用unnest。

library(tidyverse)

dt2 <- dt %>%
  mutate(label = map(label, ~map_dfr(., as.tibble))) %>%
  unnest()
dt2
# # A tibble: 5 x 6
#   mainId           id url                                             name        color default
#   <chr>         <int> <chr>                                           <chr>       <chr> <lgl>  
# 1 216226960 431676528 https://api.github.com/repos/emergenzeHack/ter~ per svilup~ d4c5~ F      
# 2 216226960 442034204 https://api.github.com/repos/emergenzeHack/ter~ sito princ~ 5319~ F      
# 3 215647494 442051239 https://api.github.com/repos/emergenzeHack/ter~ mappa       0052~ F      
# 4 215647494 431676528 https://api.github.com/repos/emergenzeHack/ter~ per svilup~ d4c5~ F      
# 5 215647494 442034204 https://api.github.com/repos/emergenzeHack/ter~ sito princ~ 5319~ F

【讨论】：

或类似选项dt %>% mutate(label = map(label, ~map_df(.x, flatten_dfr))) %>% unnest

【解决方案3】：

我认为具体问题的答案（第一个参数是什么）是"label" 列中的列表嵌套太深，并且在最高级别它们未命名。在 traceback() 输出之后，bind_rows 调用中的“x”被一一传递给 bind_rows_ 并被卡住。：

#Notice: 
#list(list(structure(list(id = 431676528L, ....


names( dt[["label"]][1] )
NULL

dt[["label"]][1]
#----------------
 dt[["label"]][1]
[[1]]
[[1]][[1]]
[[1]][[1]]$id
[1] 431676528

[[1]][[1]]$url
[1] "https://api.github.com/repos/emergenzeHack/terremotocentro/labels/per%20sviluppatori"

[[1]][[1]]$name
[1] "per sviluppatori"

[[1]][[1]]$color
[1] "d4c5f9"

[[1]][[1]]$default
[1] FALSE


[[1]][[2]]
[[1]][[2]]$id
[1] 442034204

[[1]][[2]]$url
[1] "https://api.github.com/repos/emergenzeHack/terremotocentro/labels/sito%20principale"

[[1]][[2]]$name
[1] "sito principale"

[[1]][[2]]$color
[1] "5319e7"

[[1]][[2]]$default
[1] FALSE

【讨论】：