你只需要用NAs替换你的NULL：

  require（RJSONIO）

 json_file<  - '[{ name：Doe，John，group：Red，age（y）：24，height（cm）：182，wieght（kg）：74.8，score }，
 {name：Doe，Jane，group：Green，age（y）：30，height（cm）：170，wieght（kg） 70.1，score：500}，
 {name：Smith，Joan，group：Yellow，age（y）：41，height（cm） wieght（kg）：60，score：null}，
 {name：Brown，Sam，group：Green，age（y）：22， （cm）：183，wieght（kg）：75，score：865}，
 {name：Jones，Larry，group：Green ）：31，height（cm）：178，wieght（kg）：83.9，score：221}，
 {name：Murray，Seth，group红色，年龄（y）：35，身高（cm）：172，wieght（kg）：76.2，score：413}，
 {name ，group：Yellow，age（y）：22，height（cm）：164，wieght（kg）：68，score：902}]'


j son_file<  -  fromJSON（json_file）

 json_file<  -  lapply（json_file，function（x）{
x [sapply（x，is.null）]<  -  NA 
 unlist（x）
}）
 

一旦你有一个非空值元素，您可以调用 rbind 而不会收到错误：

  do。 call（rbind，json_file）
 name group age（y）height（cm）wieght（kg）score 
 [1，]Doe，JohnRed24182 74.8NA 
 [2，]Doe，Jane绿色3017070.1500
 [3，]史密斯，琼黄41 16960NA 
 [4，]布朗，山姆绿色2218375865
 [5，]琼斯，拉里 3117883.9221
 [6，]Murray，Seth红色3517276.2413
 [7，] Doe，Jane黄色2216468902
 

I have a file containing over 1500 json objects that I want to work with in R. I've been able to import the data as a list, but am having trouble coercing it into a useful structure. I want to create a data frame containing a row for each json object and a column for each key:value pair.

I've recreated my situation with this small, fake data set:

[{"name":"Doe, John","group":"Red","age (y)":24,"height (cm)":182,"wieght (kg)":74.8,"score":null},
{"name":"Doe, Jane","group":"Green","age (y)":30,"height (cm)":170,"wieght (kg)":70.1,"score":500},
{"name":"Smith, Joan","group":"Yellow","age (y)":41,"height (cm)":169,"wieght (kg)":60,"score":null},
{"name":"Brown, Sam","group":"Green","age (y)":22,"height (cm)":183,"wieght (kg)":75,"score":865},
{"name":"Jones, Larry","group":"Green","age (y)":31,"height (cm)":178,"wieght (kg)":83.9,"score":221},
{"name":"Murray, Seth","group":"Red","age (y)":35,"height (cm)":172,"wieght (kg)":76.2,"score":413},
{"name":"Doe, Jane","group":"Yellow","age (y)":22,"height (cm)":164,"wieght (kg)":68,"score":902}]

Some features of the data:

• The objects all contain the same number of key:value pairs although some of the values are null
• There are two non-numeric columns per object (name and group)
• name is the unique identifier, there are 10 or so groups
• many of the name and group entires contain spaces, commas and other punctuation.

Based on this question: R list(structure(list())) to data frame, I tried the following:

json_file <- "test.json"
json_data <- fromJSON(json_file)
asFrame <- do.call("rbind.fill", lapply(json_data, as.data.frame))

With both my real data and this fake data, the last line give me this error:

Error in data.frame(name = "Doe, John", group = "Red", `age (y)` = 24,  : 
  arguments imply differing number of rows: 1, 0

You just need to replace your NULLs with NAs:

require(RJSONIO)    

json_file <-  '[{"name":"Doe, John","group":"Red","age (y)":24,"height (cm)":182,"wieght (kg)":74.8,"score":null},
    {"name":"Doe, Jane","group":"Green","age (y)":30,"height (cm)":170,"wieght (kg)":70.1,"score":500},
    {"name":"Smith, Joan","group":"Yellow","age (y)":41,"height (cm)":169,"wieght (kg)":60,"score":null},
    {"name":"Brown, Sam","group":"Green","age (y)":22,"height (cm)":183,"wieght (kg)":75,"score":865},
    {"name":"Jones, Larry","group":"Green","age (y)":31,"height (cm)":178,"wieght (kg)":83.9,"score":221},
    {"name":"Murray, Seth","group":"Red","age (y)":35,"height (cm)":172,"wieght (kg)":76.2,"score":413},
    {"name":"Doe, Jane","group":"Yellow","age (y)":22,"height (cm)":164,"wieght (kg)":68,"score":902}]'


json_file <- fromJSON(json_file)

json_file <- lapply(json_file, function(x) {
  x[sapply(x, is.null)] <- NA
  unlist(x)
})

Once you have a non-null value for each element, you can call rbind without getting an error:

do.call("rbind", json_file)
     name           group    age (y) height (cm) wieght (kg) score
[1,] "Doe, John"    "Red"    "24"    "182"       "74.8"      NA   
[2,] "Doe, Jane"    "Green"  "30"    "170"       "70.1"      "500"
[3,] "Smith, Joan"  "Yellow" "41"    "169"       "60"        NA   
[4,] "Brown, Sam"   "Green"  "22"    "183"       "75"        "865"
[5,] "Jones, Larry" "Green"  "31"    "178"       "83.9"      "221"
[6,] "Murray, Seth" "Red"    "35"    "172"       "76.2"      "413"
[7,] "Doe, Jane"    "Yellow" "22"    "164"       "68"        "902"