R将数据帧转换为JSON [英] R convert dataframe to JSON

问题描述

我有一个要转换为json格式的数据框：

I have a dataframe that I'd like to convert to json format:

我的数据框称为res1：

my data frame called res1:

library(rjson)

structure(list(id = c(1, 2, 3, 4, 5), value = structure(1:5, .Label = c("server1", 
"server2", "server3", "server4", "server5"), class = "factor")), .Names = c("id", 
"value"), row.names = c(NA, -5L), class = "data.frame")

当我这样做时：

toJSON(res1)

我明白了：

{"id":[1,2,3,4,5],"value":["server1","server2","server3","server4","server5"]}

我需要这个json输出像这样，有什么想法吗？

I need this json output to be like this, any ideas?

[{"id":1,"value":"server1"},{"id":2,"value":"server2"},{"id":3,"value":"server3"},{"id":4,"value":"server4"},{"id":5,"value":"server5"}]

推荐答案

怎么样

library(rjson)
x <- toJSON(unname(split(res1, 1:nrow(res1))))
cat(x)
# [{"id":1,"value":"server1"},{"id":2,"value":"server2"},
# {"id":3,"value":"server3"},{"id":4,"value":"server4"},
# {"id":5,"value":"server5"}]

通过使用 split（），我们实际上将大data.frame分解为每一行的单独data.frame。通过从结果列表中删除名称， toJSON 函数将结果包装在数组中，而不是命名对象中。

By using split() we are essentially breaking up the large data.frame into a separate data.frame for each row. And by removing the names from the resulting list, the toJSON function wraps the results in an array rather than a named object.

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