如何访问JSON数组数据? [英] How do I access JSON array data?

问题描述

我有以下数组:

[ { "attributes": {
      "id":   "usdeur",
      "code": 4
    },
    "name": "USD/EUR"
  },
  { "attributes": {
      "id":   "eurgbp",
      "code": 5
    },
    "name": "EUR/GBP"
  }
]

如何获取两个ID以便进一步处理作为输出?

How can I get both ids for futher processing as output?

我尝试了很多，但没有成功.我的问题是，我总是只获得一个id作为输出:

I tried a lot but no success. My problem is I always get only one id as output:

Market.all.select.each do |market|
  present market.id
end

或者:

Market.all.each{|attributes| present attributes[:id]}

当我需要两个ID时，结果只给我"eurgbp".

which gives me only "eurgbp" as a result while I need both ids.

推荐答案

JSON#parse应该可以帮助您

require 'json'

json = '[ { "attributes": {
             "id":   "usdeur",
             "code": 4
           },
            "name": "USD/EUR"
           },
         { "attributes": {
            "id":   "eurgbp",
            "code": 5
           },
           "name": "EUR/GBP"
         }]'

ids = JSON.parse(json).map{|hash| hash['attributes']['id'] }
#=> ["usdeur", "eurgbp"]

JSON#parse将jSON响应转换为Hash，然后仅使用标准的Hash方法进行访问.

JSON#parse turns a jSON response into a Hash then just use standard Hash methods for access.

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