r - 在 R 中使用 jsonlite 时，如何指定仅将某些条目视为数组？

Question

我有以下代码:

# install.packages("jsonlite")
require("jsonlite")
x = list(
    test = "my_test",
    data = c(1, 2, 3)
)
toJSON(x)

这打印:

{"test":["my_test"],"data":[1,2,3]} 

我期待:

{"test":"my_test","data":[1,2,3]}

我尝试使用 documentation 中的一些参数, 但似乎无法正确处理。

Answer 1

参数 auto_unbox=TRUE 起到了作用:

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.

即，解决方案是 toJSON(x, auto_unbox=TRUE)，它返回我预期的结果:

{"test":"my_test","data":[1,2,3]}