ruby JSON操作

以下为JSON数据，将该数据存储在 input.json 文件中：

{
  "President": "Alan Isaac",
  "CEO": "David Richardson",
  
  "India": [
    "Sachin Tendulkar",
    "Virender Sehwag",
    "Gautam Gambhir",
  ],

  "Srilanka": [
    "Lasith Malinga",
    "Angelo Mathews",
    "Kumar Sangakkara"
  ],

  "England": [
    "Alastair Cook",
    "Jonathan Trott",
    "Kevin Pietersen"
  ]
}

以下的 Ruby 程序用于解析以上 JSON 文件；

#!/usr/bin/ruby
require 'rubygems'
require 'json'
require 'pp'

json = File.read('input.json')
obj = JSON.parse(json)

pp obj
pp obj['President']
pp obj['England'][0]
puts obj['England'][0] #=>体现puts和pp在输出结果方面的不同

以上实例执行结果为：

{"President"=>"Alan Isaac",
 "CEO"=>"David Richardson",

 "India"=>
  ["Sachin Tendulkar", "Virender Sehwag", "Gautam Gambhir"],

"Srilanka"=>
  ["Lasith Malinga ", "Angelo Mathews", "Kumar Sangakkara"],

 "England"=>
  ["Alastair Cook", "Jonathan Trott", "Kevin Pietersen"]
}

"Alan Isaac"
"Alastair Cook"
Alastair Cook

example2：

Here are some examples:

hash_of_values = {'foo' => 1, 'bar' => 2}
array_of_values = [hash_of_values]

JSON[hash_of_values] 
# => "{\"foo\":1,\"bar\":2}"

JSON[array_of_values] 
# => "[{\"foo\":1,\"bar\":2}]"

string_to_parse = array_of_values.to_json
JSON[string_to_parse]
# => [{"foo"=>1, "bar"=>2}] （return一个数组）

JSON.parse(JSON[array_of_values]) 返回一个数组
JSON.parse(JSON[hash_of_values]) 返回一个哈希

If you root around in JSON you might notice it's a subset of YAML, and, actually the YAML parser is what's handling JSON. You can do this too:

require 'yaml'

YAML.load(string_to_parse)
# => [{"foo"=>1, "bar"=>2}]