從 R 中的 JSON 文件中刪除方括號

Question

我正在 R 中創建一個 JSON 文件：

test <- c(list(item1 = "TEXT",
               item2 = as.array(list(start = 0,
                                     end = 99))))

write_json(test, path = "test.json" , auto_unbox = TRUE , null = "null")

這導致：

{"item1":"INDIVIDUAL_AGE","item2":{"start":[0],"end":[99]}}

但是我需要結果是：

{"item1":"INDIVIDUAL_AGE","item2":{"start":0,"end":99}}

如何擺脫 item2 元素中的方括號？

Answer 1

對於auto_unbox ， jsonlite::toJSON推薦unbox ：

auto_unbox: automatically 'unbox' all atomic vectors of length 1. It is
          usually safer to avoid this and instead use the 'unbox'
          function to unbox individual elements. An exception is that
          objects of class 'AsIs' (i.e. wrapped in 'I()') are not
          automatically unboxed. This is a way to mark single values as
          length-1 arrays.

為此，我們可以使用rapply ：

library(jsonlite)
toJSON(
  rapply(test, function(z) if (length(z) == 1L) unbox(z) else z,
         how = "replace")
)
# {"item1":"TEXT","item2":{"start":0,"end":99}} 

（也適用於write_json 。）

_{...雖然對我來說auto_unbox=TRUE在這里不起作用似乎很奇怪。}