R - JSON 檔案

JSON 檔案以人類可讀的格式將資料儲存為文字。JSON 代表 JavaScript 物件表示法。R 可以使用 rjson 包讀取 JSON 檔案。

安裝 rjson 包

在 R 控制檯中，您可以發出以下命令來安裝 rjson 包：

install.packages("rjson")

輸入資料

透過將以下資料複製到記事本等文字編輯器中來建立一個 JSON 檔案。將檔案儲存為 **.json** 副檔名，並將檔案型別選擇為 **所有檔案（*.*）**。

{ 
   "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"]
}

讀取 JSON 檔案

JSON 檔案使用 **fromJSON()** 函式由 R 讀取。它作為 R 中的一個列表儲存。

# 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)

當我們執行上述程式碼時，它會產生以下結果：

$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"

將 JSON 轉換為資料框

我們可以使用 **as.data.frame()** 函式將上面提取的資料轉換為 R 資料框，以便進一步分析。

# 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)

當我們執行上述程式碼時，它會產生以下結果：

      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