我正在尝试显示此数据集 - ＆gt; https://mtgjson.com/json/AllSets.json.zip
但是，我希望将数据展平，以便它不会嵌套在列表中，列表内的列表中的一堆JSON数据中。
更具体地说，我试图将数据显示为数据帧，按$releaseDate（其中一个变量）的顺序排列。
到目前为止，这是我的尝试：
library(jsonlite)
library(tidyjson)
mtgdata <- fromJSON("~/path/to/file.json")
mtgdata的结果显示了这个列表列表：
summary(mtgdata)
Length Class Mode
UST 9 -none- list
UNH 10 -none- list
UGL 11 -none- list
pWOS 8 -none- list
pWOR 8 -none- list
pWCQ 8 -none- list
pSUS 8 -none- list
pSUM 10 -none- list
pREL 8 -none- list
pPRO 8 -none- list
pPRE 8 -none- list
pPOD 7 -none- list
pMPR 8 -none- list
pMGD 8 -none- list
pMEI 8 -none- list
pLPA 8 -none- list
pLGM 8 -none- list
pJGP 10 -none- list
pHHO 11 -none- list
pWPN 8 -none- list
pGTW 8 -none- list
pGRU 10 -none- list
pGPX 8 -none- list
pFNM 10 -none- list
pELP 8 -none- list
pDRC 7 -none- list
pCMP 8 -none- list
pCEL 8 -none- list
pARL 8 -none- list
pALP 10 -none- list
p2HG 8 -none- list
p15A 8 -none- list
PD3 9 -none- list
PD2 9 -none- list
H09 9 -none- list
PTK 12 -none- list
POR 12 -none- list
PO2 13 -none- list
PCA 7 -none- list
PC2 10 -none- list
HOP 10 -none- list
VMA 9 -none- list
MMA 10 -none- list
MM3 8 -none- list
MM2 11 -none- list
MED 9 -none- list
ME4 9 -none- list
ME3 9 -none- list
ME2 9 -none- list
IMA 8 -none- list
EMA 9 -none- list
A25 8 -none- list
MPS_AKH 8 -none- list
MPS 9 -none- list
EXP 9 -none- list
E02 7 -none- list
V17 8 -none- list
V16 7 -none- list
V15 9 -none- list
V14 9 -none- list
V13 9 -none- list
V12 10 -none- list
V11 10 -none- list
V10 9 -none- list
V09 10 -none- list
DRB 9 -none- list
EVG 9 -none- list
DDT 7 -none- list
DDS 7 -none- list
DDR 7 -none- list
DDQ 8 -none- list
DDP 10 -none- list
DDO 10 -none- list
DDN 10 -none- list
DDM 10 -none- list
DDL 10 -none- list
DDK 10 -none- list
DDJ 10 -none- list
DDI 10 -none- list
DDH 10 -none- list
DDG 10 -none- list
DDF 10 -none- list
DDE 10 -none- list
DDD 9 -none- list
DDC 9 -none- list
DD3_JVC 9 -none- list
DD3_GVL 9 -none- list
DD3_EVG 9 -none- list
DD3_DVD 9 -none- list
DD2 11 -none- list
CNS 11 -none- list
CN2 9 -none- list
CMD 11 -none- list
CMA 7 -none- list
CM1 10 -none- list
C17 6 -none- list
C16 8 -none- list
C15 10 -none- list
C14 10 -none- list
C13 10 -none- list
CEI 9 -none- list
CED 9 -none- list
E01 7 -none- list
ARC 9 -none- list
ZEN 12 -none- list
XLN 12 -none- list
WWK 12 -none- list
WTH 13 -none- list
W17 8 -none- list
W16 8 -none- list
VIS 13 -none- list
VAN 8 -none- list
USG 13 -none- list
ULG 13 -none- list
UDS 13 -none- list
TSP 12 -none- list
TSB 12 -none- list
TPR 11 -none- list
TOR 12 -none- list
TMP 13 -none- list
THS 12 -none- list
STH 13 -none- list
SOM 12 -none- list
SOK 12 -none- list
SOI 10 -none- list
SHM 12 -none- list
SCG 12 -none- list
S99 11 -none- list
S00 11 -none- list
RTR 12 -none- list
RQS 6 -none- list
ROE 12 -none- list
RIX 12 -none- list
RAV 12 -none- list
PLS 13 -none- list
PLC 12 -none- list
PCY 13 -none- list
ORI 11 -none- list
ONS 12 -none- list
OGW 10 -none- list
ODY 13 -none- list
NPH 12 -none- list
NMS 14 -none- list
MRD 12 -none- list
MOR 12 -none- list
MMQ 13 -none- list
MIR 13 -none- list
MGB 10 -none- list
MD1 9 -none- list
MBS 12 -none- list
M15 11 -none- list
M14 11 -none- list
M13 11 -none- list
M12 11 -none- list
M11 11 -none- list
M10 11 -none- list
LRW 12 -none- list
LGN 12 -none- list
LEG 12 -none- list
LEB 11 -none- list
LEA 11 -none- list
KTK 12 -none- list
KLD 9 -none- list
JUD 12 -none- list
JOU 12 -none- list
ITP 11 -none- list
ISD 12 -none- list
INV 13 -none- list
ICE 13 -none- list
HOU 9 -none- list
HML 12 -none- list
GTC 12 -none- list
GPT 12 -none- list
FUT 12 -none- list
FRF_UGIN 10 -none- list
FRF 12 -none- list
FEM 11 -none- list
EXO 13 -none- list
EVE 12 -none- list
EMN 9 -none- list
DTK 12 -none- list
DST 12 -none- list
DRK 12 -none- list
DPA 9 -none- list
DKM 9 -none- list
DKA 12 -none- list
DIS 12 -none- list
DGM 12 -none- list
CST 11 -none- list
CSP 12 -none- list
CP3 7 -none- list
CP2 7 -none- list
CP1 7 -none- list
CON 13 -none- list
CHR 11 -none- list
CHK 12 -none- list
BTD 10 -none- list
BRB 10 -none- list
BOK 12 -none- list
BNG 12 -none- list
BFZ 12 -none- list
AVR 12 -none- list
ATQ 11 -none- list
ATH 9 -none- list
ARN 11 -none- list
ARB 12 -none- list
APC 13 -none- list
ALL 13 -none- list
ALA 12 -none- list
AKH 9 -none- list
AER 9 -none- list
9ED 12 -none- list
8ED 12 -none- list
7ED 12 -none- list
6ED 12 -none- list
5ED 12 -none- list
5DN 12 -none- list
4ED 12 -none- list
3ED 12 -none- list
2ED 11 -none- list
10E 11 -none- list
在每个列表中都有我感兴趣的分析变量，以便对这些数据进行过滤和排序，就像它是一个展平的数据帧一样。
当我们检查其中一个列表中的变量列表时（以“mtgdata $ UST”为例），我们得到了这组变量：
names(mtgdata$UST)
[1] "name" "code" "releaseDate" "border" "type"
"booster" "mkm_name"
[8] "mkm_id" "cards"
在mtgdata（“mtgdata $ SOI”）中的另一个列表上运行相同的查询，我们得到另一组变量，尽管它们大多是相同的。
正如我上面提到的，我主要对通过mtgdata $ releaseDate展平此数据集和排名感兴趣 - 但就目前而言，“$ releaseDate”目前嵌套在第一组列表中（“$ UST”等）。 ）
我对此问题的帮助或如何更好地重新解释这个问题将不胜感激。
答案 0 :(得分：0)
您可以在命令行上尝试类似this的内容，将JSON对象数组转换为文件ndjson记录，然后使用类似ndjson::stream_in("filename_of the_thing_you_just_converted")的内容，但最终会得到14,000+列，相当无用，“扁平”的数据框架。
相反，做一些洞察：
library(tidyverse)
as1 <- jsonlite::read_json("~/Downloads/AllSets.json")
str(as1, 1)
## List of 221
## $ UST :List of 9
## $ UNH :List of 10
## $ UGL :List of 11
## $ pWOS :List of 8
## $ pWOR :List of 8
## $ pWCQ :List of 8
## $ pSUS :List of 8
## $ pSUM :List of 10
## $ pREL :List of 8
## $ pPRO :List of 8
## $ pPRE :List of 8
## $ pPOD :List of 7
## $ pMPR :List of 8
## $ pMGD :List of 8
## $ pMEI :List of 8
## $ pLPA :List of 8
## $ pLGM :List of 8
## $ pJGP :List of 10
## $ pHHO :List of 11
## ...
呃...其中一个“那些”JSON文件看起来不适合让每个记录的所有元素都填充，即使整个文件 - 理论上 - 应该是一致的。
让我们看看哪些JSON数组元素填充的字段数最多，因为这意味着可能已经填充了所有字段：
map_dbl(as1, length) %>%
broom::tidy() %>%
arrange(desc(x))
## # A tibble: 221 x 2
## names x
## <chr> <dbl>
## 1 NMS 14.0
## 2 PO2 13.0
## 3 WTH 13.0
## 4 VIS 13.0
## 5 USG 13.0
## 6 ULG 13.0
## 7 UDS 13.0
## 8 TMP 13.0
## 9 STH 13.0
## 10 PLS 13.0
## # ... with 211 more rows
我们来看看NMS：
str(as1[["NMS"]], 1)
## List of 14
## $ name : chr "Nemesis"
## $ code : chr "NMS"
## $ gathererCode : chr "NE"
## $ magicCardsInfoCode: chr "ne"
## $ oldCode : chr "NEM"
## $ releaseDate : chr "2000-02-14"
## $ border : chr "black"
## $ type : chr "expansion"
## $ block : chr "Masques"
## $ booster :List of 15
## $ translations :List of 5
## $ mkm_name : chr "Nemesis"
## $ mkm_id : int 32
## $ cards :List of 143
您确实不想展平booster，translations或cards，并应将其保留为list列和{{1必要时。
但是，由于每个记录都有不同的字段，我们不能简单地“data.table :: rbindlist（）unnest dplyr :: bind_rows（）”，因为它会抱怨这些列中的一些。
我们必须逐个记录并将每个转换为数据框，处理丢失的字段并将or个字段包装在list中。我们将使用辅助函数简化函数习惯，以测试缺失值：
list() ^^比使用`%l0%` <- function(x, y) if (length(x) > 0) x else y
的{{1}}更健壮。
最后：
%||%而且，你可以看到结果：
purrr并且，我们可以在将列转换为正确的map_df(as1, ~{
data_frame(
name = .x$name %l0% NA_character_,
code = .x$code,
gathererCode = .x$gathererCode %l0% NA_character_,
magicCardsInfoCode = .x$magicCardsInfoCode %l0% NA_character_,
oldCode = .x$oldCode %l0% NA_character_,
releaseDate = .x$releaseDate %l0% NA_character_,
border = .x$border,
type = .x$type,
block = .x$block %l0% NA_character_,
booster = list(.x$booster),
translations = list(.x$translations),
mkm_name = .x$mkm_name %l0% NA_character_,
mkm_id = .x$mkm_id %l0% NA_character_,
cards = list(.x$cards)
)
}) -> all_sets
对象后按all_sets
## # A tibble: 221 x 14
## name code gathererCode magicCardsInfoC… oldCode releaseDate border type block booster
## <chr> <chr> <chr> <chr> <chr> <chr> <chr> <chr> <chr> <list>
## 1 Unstable UST NA NA NA 2017-12-08 silver un NA <list […
## 2 Unhinged UNH NA uh NA 2004-11-20 silver un NA <list […
## 3 Unglued UGL UG ug NA 1998-08-11 silver un NA <list […
## 4 Wizards of th… pWOS NA wotc NA 1999-09-04 black promo NA <NULL>
## 5 Worlds pWOR NA wrl NA 1999-08-04 black promo NA <NULL>
## 6 World Magic C… pWCQ NA wmcq NA 2013-04-06 black promo NA <NULL>
## 7 Super Series pSUS NA sus NA 1999-12-01 black promo NA <NULL>
## 8 Summer of Mag… pSUM NA sum NA 2007-07-21 black promo NA <NULL>
## 9 Release Events pREL NA rep NA 2003-07-26 black promo NA <NULL>
## 10 Pro Tour pPRO NA pro NA 2007-02-09 black promo NA <NULL>
## # ... with 211 more rows, and 4 more variables: translations <list>, mkm_name <chr>, mkm_id <int>,
## # cards <list>
glimpse(all_sets)
## Observations: 221
## Variables: 14
## $ name <chr> "Unstable", "Unhinged", "Unglued", "Wizards of the Coast Online Store"...
## $ code <chr> "UST", "UNH", "UGL", "pWOS", "pWOR", "pWCQ", "pSUS", "pSUM", "pREL", "...
## $ gathererCode <chr> NA, NA, "UG", NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, ...
## $ magicCardsInfoCode <chr> NA, "uh", "ug", "wotc", "wrl", "wmcq", "sus", "sum", "rep", "pro", "pt...
## $ oldCode <chr> NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA...
## $ releaseDate <chr> "2017-12-08", "2004-11-20", "1998-08-11", "1999-09-04", "1999-08-04", ...
## $ border <chr> "silver", "silver", "silver", "black", "black", "black", "black", "bla...
## $ type <chr> "un", "un", "un", "promo", "promo", "promo", "promo", "promo", "promo"...
## $ block <chr> NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA...
## $ booster <list> [["rare", "uncommon", "uncommon", "uncommon", "common", "common", "co...
## $ translations <list> [NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NU...
## $ mkm_name <chr> "Unstable", "Unhinged", "Unglued", NA, NA, NA, NA, "Summer Magic", NA,...
## $ mkm_id <int> 1821, 59, 22, NA, NA, NA, NA, 76, NA, NA, NA, NA, NA, NA, NA, NA, NA, ...
## $ cards <list> [[["Andrea Radeck", 1, ["W"], ["White"], "95ebdf85f4ea74d584dfdfb72e3...
排列它们：
releaseDate