使用jsonlite或其他内容从R编码JSON表达式 [英] encoding a JSON expression from R with jsonlite or something else
问题描述
我使用的API需要我发送一个 JSON
消息,如:
y < - '[{a:1,b:select,c:[A,B,C]},
{a:2,b:text},
{a:3,b:select,c:[D,E ,G]}]'
请注意,在 b:select
还有另一个变量 c
,值为数组。
当我尝试从JSON(y)(在 jsonlite
包中)运行时,我得到一个
data.frame
其中第3列是列表:
> z< - 从JSON(y)
> class(z)
[1]data.frame
> z%>%glimpse()
观察:3
变量:3
$ a(int)1,2,3
$ b(chr)select文本,选择
$ c(列表)A,B,C,NULL,D,E,F,G
但是当我将其转换回 JSON
(这是我要发送给API的格式) , c
变量出现在不应该的位置。
{a:1,b:select,c:[A,B,C]},
{a:2,b文本,c:{}},
{a:3,b:select,c:[D,E,F ]}]
是否有另一个R数据结构可以可靠地让我从一个数据帧到原来的 JSON
消息使用 jsonlite
(或其他)?它如何工作?
与 jsonlite
,你可以做如下:
z < - fromJSON(y,simplifiedDataFrame = F)
toJSON(z,auto_unbox = T)
另外,考虑以下情况,最后一个 c
元素是 [D]
:
y2 < '{a:1,b:select,c:[A,B,C]},
{a:2,b :text},
{a:3,b:select,c:[D]}]'
z2< - fromJSON (y2,simplifiedDataFrame = F)
toJSON(z2,auto_unbox = T)
这个:
[{a:1,b:select,c ,B,C]},
{a:2,b:text},
{a:3,b c:D}]
这可能是一个麻烦,因为最后一个 c
元素是D
不是 [D]
p>
为了防止这种情况,请勿使用 auto_unbox
。请仔细使用 unbox
z2 < - fromJSON(y2 ,simplDataFrame = F)
for(i in 1:length(z2)){
z2 [[i]] [[1]]< - unbox(z2 [[i]] [[1 ]])
z2 [[i]] [[2]]< - unbox(z2 [[i]] [[2]])
}
toJSON(z2)
The API I'm using needs me to send it a JSON
message like:
y <- '[{"a":1, "b":"select", "c":["A", "B", "C"]},
{"a":2, "b":"text"},
{"a":3, "b":"select", "c":["D", "E", "F", "G"]}]'
Notice that in the case "b" : "select"
there is another variable c
with the value being an array.
When I try running fromJSON(y)
(in the jsonlite
package) I get a data.frame
where the 3rd column is a list:
> z <- fromJSON(y)
> class(z)
[1] "data.frame"
> z %>% glimpse()
Observations: 3
Variables: 3
$ a (int) 1, 2, 3
$ b (chr) "select", "text", "select"
$ c (list) A, B, C, NULL, D, E, F, G
But when I convert it back to JSON
(which is the format I want to send to the API), the c
variable appears where it shouldn't be.
[{"a":1,"b":"select","c":["A","B","C"]},
{"a":2,"b":"text","c":{}},
{"a":3,"b":"select","c":["D","E","F","G"]}]
Is there another R data structure that could reliably get me from a data frame to the original JSON
message using jsonlite
(or something else)? How would it work?
with jsonlite
, you can do as follows:
z <- fromJSON(y, simplifyDataFrame = F)
toJSON(z, auto_unbox=T)
In addition, consider following case where last c
element is ["D"]
:
y2 <- '[{"a":1, "b":"select", "c":["A", "B", "C"]},
{"a":2, "b":"text"},
{"a":3, "b":"select", "c":["D"]}]'
z2 <- fromJSON(y2, simplifyDataFrame = F)
toJSON(z2, auto_unbox=T)
Result is this:
[{"a":1,"b":"select","c":["A","B","C"]},
{"a":2,"b":"text"},
{"a":3,"b":"select","c":"D"}]
This can be a trouble because the last c
element is "D"
not ["D"]
.
To prevent this, don's use auto_unbox
. Use unbox
carefully as follows:
z2 <- fromJSON(y2, simplifyDataFrame = F)
for(i in 1:length(z2)){
z2[[i]][[1]] <- unbox(z2[[i]][[1]])
z2[[i]][[2]] <- unbox(z2[[i]][[2]])
}
toJSON(z2)
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