JSON文件以可读取的格式将数据存储为文本。Json是一种JavaScript对象表示法。R可以使用rjson包读取JSON文件。
安装rjson软件包
在R控制台中，您可以发出以下命令来安装rjson包。
install.packages("rjson")
准备输入数据源
通过将以下数据复制到文本编辑器(如记事本)中创建一个JSON文件。 使用.json扩展名保存文件，并将文件类型选为所有文件(*.*)。创建一个文件：input.json，其内容如下所示 -
{
"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"]
}
读取JSON文件
R使用JSON()函数读取JSON文件的内容，它作为列表存储在R中。参考以下代码 -
# 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)
当我们执行上述代码时，会产生以下结果 -
$ID
[1] "1" "2" "3" "4" "5" "6" "7" "8"
$Name
[1] "Rick" "Dan" "Michelle" "Ryan" "Gary"
[6] "Nina" "Simon" "Guru"
$Salary
[1] "623.3" "515.2" "611" "729" "843.25" "578" "632.8"
[8] "722.5"
$StartDate
[1] "1/1/2012" "9/23/2013" "11/15/2014" "5/11/2014"
[5] "3/27/2015" "5/21/2013" "7/30/2013" "6/17/2014"
$Dept
[1] "IT" "Operations" "IT" "HR"
[5] "Finance" "IT" "Operations" "Finance"
将JSON转换为数据帧
我们可以将上述提取的数据通过使用as.data.frame()函数转换为R数据帧，以便进一步分析。
# 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)
当我们执行上述代码时，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
