JSON 文件

JSON文件以人类可读的格式将数据存储为文本。 Json代表JavaScript Object Notation。 R可以使用rjson包读取JSON文件。

安装rjson包

在R控制台中，您可以发出以下命令来安装rjson包。

install.packages("rjson")

输入数据 (Input Data)

通过将以下数据复制到文本编辑器（如记事本）来创建JSON文件。 使用.json扩展名保存文件，并选择文件类型作为all files(*.*) 。

{ 
   "ID":["1","2","3","4","5","6","7","8" ],
   "Name":["Rick","Dan","Michelle","Ryan","Gary","Nina","Simon","Guru" ],
   "Salary":["623.3","515.2","611","729","843.25","578","632.8","722.5" ],
   "StartDate":[ "1/1/2012","9/23/2013","11/15/2014","5/11/2014","3/27/2015","5/21/2013",
      "7/30/2013","6/17/2014"],
   "Dept":[ "IT","Operations","IT","HR","Finance","IT","Operations","Finance"]
}

阅读JSON文件

R使用JSON()函数读取JSON文件。 它作为列表存储在R中。

# Load the package required to read JSON files.
library("rjson")
# Give the input file name to the function.
result <- fromJSON(file = "input.json")
# Print the result.
print(result)

当我们执行上面的代码时，它会产生以下结果 -

$ID
[1] "1"   "2"   "3"   "4"   "5"   "6"   "7"   "8"
$Name
[1] "Rick"     "Dan"      "Michelle" "Ryan"     "Gary"     "Nina"     "Simon"    "Guru"
$Salary
[1] "623.3"  "515.2"  "611"    "729"    "843.25" "578"    "632.8"  "722.5"
$StartDate
[1] "1/1/2012"   "9/23/2013"  "11/15/2014" "5/11/2014"  "3/27/2015"  "5/21/2013"
   "7/30/2013"  "6/17/2014"
$Dept
[1] "IT"         "Operations" "IT"         "HR"         "Finance"    "IT"
   "Operations" "Finance"

将JSON转换为数据框

我们可以将上面提取的数据转换为R数据帧，以便使用as.data.frame()函数进行进一步分析。

# Load the package required to read JSON files.
library("rjson")
# Give the input file name to the function.
result <- fromJSON(file = "input.json")
# Convert JSON file to a data frame.
json_data_frame <- as.data.frame(result)
print(json_data_frame)

当我们执行上面的代码时，它会产生以下结果 -

      id,   name,    salary,   start_date,     dept
1      1    Rick     623.30    2012-01-01      IT
2      2    Dan      515.20    2013-09-23      Operations
3      3    Michelle 611.00    2014-11-15      IT
4      4    Ryan     729.00    2014-05-11      HR
5     NA    Gary     843.25    2015-03-27      Finance
6      6    Nina     578.00    2013-05-21      IT
7      7    Simon    632.80    2013-07-30      Operations
8      8    Guru     722.50    2014-06-17      Finance