How can I convert a string of JSON data to a multidimensional array?
# Begin with JSON
json_data = "[
{"id":1,"name":"Don"},
{"id":2,"name":"Bob"},
...
]"
# do something here to convert the JSON data to array of arrays.
# End with multidimensional arrays
array_data = [
["id", "name"],
[1,"Don"],
[2,"Bob"],
...
]
For readability and efficiency, I would do it like this:
require 'json'
json_data = '[{"id":1,"name":"Don"},{"id":2,"name":"Bob"}]'
arr = JSON.parse(json_data)
#=> "[{\"id\":1,\"name\":\"Don\"},{\"id\":2,\"name\":\"Bob\"}]"
keys = arr.first.keys
#=> ["id", "name"]
arr.map! { |h| h.values_at(*keys) }.unshift(keys)
#=> [["id", "name"], [1, "Don"], [2, "Bob"]]
This should do the trick:
require 'json'
json_data = '[{"id":1,"name":"Don"},{"id":2,"name":"Bob"}]'
JSON.parse(json_data).inject([]) { |result, e| result + [e.keys, e.values] }.uniq
First, we read the JSON into an array with JSON.parse. For each element in the JSON, we collect all keys and values using inject which results in the following array:
[
["id", "name"],
[1, "Don"],
["id", "name"],
[2, "Bob"]
]
To get rid of the repeating key-arrays, we call uniq and are done.
[
["id", "name"],
[1, "Don"],
[2, "Bob"]
]
Adding to @tessi's answer, we can avoid using 'uniq' if we combine 'with_index' and 'inject'.
require 'json'
json_data = '[{"id":1,"name":"Don"},{"id":2,"name":"Bob"}]'
array_data = JSON.parse(json_data).each.with_index.inject([]) { |result, (e, i)| result + (i == 0 ? [e.keys, e.values] : [e.values]) }
puts array_data.inspect
The result is:
[["id", "name"], [1, "Don"], [2, "Bob"]]
