如何将JSON导入R并将其转换为表? [英] How to import JSON into R and convert it to table?

问题描述

我想播放现在以JSON格式保存的数据.但是我对R非常陌生，对如何处理数据一无所知.您可以在下面看到我设法实现的目标.但是首先，我的代码:

I want to play with data that is now saved in JSON format. But I am very new to R and have little clue of how to play with data. You can see below what I managed to achieve. But first, my code:

library(rjson)
json_file <- "C:\\Users\\Saonkfas\\Desktop\\WOWPAPI\\wowpfinaljson.json"
json_data <- fromJSON(paste(readLines(json_file), collapse=""))

我能够得到数据:

for (x in json_data){print (x)}

尽管输出看起来很原始:

Although output looks pretty raw:

[[1]]
[[1]]$wins
[1] "118"

[[1]]$losses
[1] "40"
# And so on

请注意，JSON有点嵌套.我可以用Python创建表，但是R似乎要复杂得多.

Note that the JSON is somewhat nested. I could create tables with Python, but R seems much more complicated.

我的JSON:

{
"play1": [
    {
        "wins": "118",
        "losses": "40",
        "max_killed": "7",
        "battles": "158",
        "plane_id": "4401",
        "max_ground_object_destroyed": "3"
    },
    {
        "wins": "100",
        "losses": "58",
        "max_killed": "7",
        "battles": "158",
        "plane_id": "2401",
        "max_ground_object_destroyed": "3"
    },
    {
        "wins": "120",
        "losses": "38",
        "max_killed": "7",
        "battles": "158",
        "plane_id": "2403",
        "max_ground_object_destroyed": "3"
    }
],

"play2": [
    {
        "wins": "12",
        "losses": "450",
        "max_killed": "7",
        "battles": "158",
        "plane_id": "4401",
        "max_ground_object_destroyed": "3"
    },
    {
        "wins": "150",
        "losses": "8",
        "max_killed": "7",
        "battles": "158",
        "plane_id": "2401",
        "max_ground_object_destroyed": "3"
    },
    {
        "wins": "120",
        "losses": "328",
        "max_killed": "7",
        "battles": "158",
        "plane_id": "2403",
        "max_ground_object_destroyed": "3"
    }
],

推荐答案

fromJSON返回一个列表，您可以使用*apply函数遍历每个元素. 将其转换为表"(数据框是正确的R术语)非常简单(一旦您知道该怎么做！).

fromJSON returns a list, you can use the *apply functions to go through each element. It's fairly straightforward (once you know what to do!) to convert it to a "table" (data frame is the correct R terminology).

library(rjson)

# You can pass directly the filename
my.JSON <- fromJSON(file="test.json")

df <- lapply(my.JSON, function(play) # Loop through each "play"
  {
  # Convert each group to a data frame.
  # This assumes you have 6 elements each time
  data.frame(matrix(unlist(play), ncol=6, byrow=T))
  })

# Now you have a list of data frames, connect them together in
# one single dataframe
df <- do.call(rbind, df)

# Make column names nicer, remove row names
colnames(df) <- names(my.JSON[[1]][[1]])
rownames(df) <- NULL

df
  wins losses max_killed battles plane_id max_ground_object_destroyed
1  118     40          7     158     4401                           3
2  100     58          7     158     2401                           3
3  120     38          7     158     2403                           3
4   12    450          7     158     4401                           3
5  150      8          7     158     2401                           3
6  120    328          7     158     2403                           3

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