Ruby 为什么我会得到；没有将字符串隐式转换为整数（TypeError）“；？

我有一些代码，我在非常相似的情况下运行。这是第一种情况，我需要一部电影的

imdb\u id

：

url = "http://mymovieapi.com/?id=#{self.imdb_id}&type=json&plot=none&episode=0&lang=en-US&aka=simple&release=simple&business=0&tech=0"
doc = Hpricot(open(url)).to_s
json = JSON.parse(doc)

puts json
puts json["imdb_id"]

这将得到以下结果：

{"rating_count"=>493949,
"genres"=>["Drama", "Romance"],
"rated"=>"PG-13",
"language"=>["English", "French", "German", "Swedish", "Italian", "Russian"],
"rating"=>7.6,
"country"=>["USA"],
"release_date"=>19980403,
"title"=>"Titanic",
"year"=>1997,
"filming_locations"=>"Santa Clarita, California, USA",
"imdb_id"=>"tt0120338",
"directors"=>["James Cameron"],
"writers"=>["James Cameron"],
"actors"=>["Leonardo DiCaprio", "Kate Winslet", "Billy Zane", "Kathy Bates", "Frances Fisher", "Gloria Stuart", "Bill Paxton", "Bernard Hill", "David Warner", "Victor Garber", "Jonathan Hyde", "Suzy Amis", "Lewis Abernathy", "Nicholas Cascone", "Anatoly M. Sagalevitch"],
"also_known_as"=>["Tai tan ni ke hao"],
"poster"=>{"imdb"=>"http://ia.media-imdb.com/images/M/MV5BMjExNzM0NDM0N15BMl5BanBnXkFtZTcwMzkxOTUwNw@@._V1_SY317_CR0,0,214,317_.jpg", "cover"=>"http://imdb-poster.b0.upaiyun.com/000/120/338.jpg!cover?_upt=66ac07591382594194"},
"runtime"=>["194 min"],
"type"=>"M",
"imdb_url"=>"http://www.imdb.com/title/tt0120338/"}

tt0120338

这是意料之中的。在第二种情况下，我拥有同一部电影的

标题

和

年份

：

url = "http://mymovieapi.com/?title=#{self.title}&type=json&plot=simple&episode=0&limit=1&year=#{self.year}&yg=1&mt=none&lang=en-US&offset=&aka=simple&release=simple&business=0&tech=0"
doc = Hpricot(open(url)).to_s
json = JSON.parse(doc)

puts json
puts json["imdb_id"]

由此，我得到了完全相同的JSON输出：

{"rating_count"=>493949,
"genres"=>["Drama", "Romance"],
"rated"=>"PG-13", "language"=>["English", "French", "German", "Swedish", "Italian", "Russian"],
"rating"=>7.6,
"country"=>["USA"],
"release_date"=>19980403,
"title"=>"Titanic",
"year"=>1997,
"filming_locations"=>"Santa Clarita, California, USA",
"imdb_id"=>"tt0120338",
"directors"=>["James Cameron"],
"writers"=>["James Cameron"],
"actors"=>["Leonardo DiCaprio", "Kate Winslet", "Billy Zane", "Kathy Bates", "Frances Fisher", "Gloria Stuart", "Bill Paxton", "Bernard Hill", "David Warner", "Victor Garber", "Jonathan Hyde", "Suzy Amis", "Lewis Abernathy", "Nicholas Cascone", "Anatoly M. Sagalevitch"],
"also_known_as"=>["Tai tan ni ke hao"],
"poster"=>{"imdb"=>"http://ia.media-imdb.com/images/M/MV5BMjExNzM0NDM0N15BMl5BanBnXkFtZTcwMzkxOTUwNw@@._V1_SY317_CR0,0,214,317_.jpg",
"cover"=>"http://imdb-poster.b0.upaiyun.com/000/120/338.jpg!cover?_upt=ec8bdec31382594417"},
"runtime"=>["194 min"],
"type"=>"M",
"imdb_url"=>"http://www.imdb.com/title/tt0120338/"}

但是当我尝试调用

puts json[“imdb\u id”]

时，我得到了以下错误：

no implicit conversion of String into Integer (TypeError)

---

当使用

标题
和
年份
进行获取时，这种情况总是会发生，但由于JSON输出完全相同，因此它似乎无法解释。
从异常情况来看，第二个响应中的
JSON
似乎是一个只有一个元素的数组，因此
puts JSON
的输出是相同的（括号不能通过
put
）获得输出，但是
json[“string”]
失败，因为
[]
希望使用
整数作为索引

检查
p json
或
json.is_a？（Array）
如果它确实是一个数组，请尝试使用
json。首先['imdb_id']
根据我的判断，错误一定在代码的其他地方

我将您提供的JSON设置为IRB中变量
a
的输出：（第二个示例中的JSON）

然后我打电话：

1.9.3p194 :046 > puts a["imdb_id"]
tt0120338
 => nil 

这给了我正确的输出。
以下是问题所在和解决方法：


您没有返回HTML，因此不需要解析HTML。请查看下面示例中的
doc
内容。请注意，没有正在进行的HTML解析，也没有任何需要，因为您特别请求JSON响应：
type=JSON
第一个请求返回一个响应，因为您请求的是一个特定的
imdb\u id
。您只能返回一个响应，因此只能得到一个对象/散列
第二个请求返回一个响应数组，因为可能有多个项目具有相同的
标题
和
年份
，但这似乎不太可能。因此，在解析JSON后，您必须从返回的数组中获取特定项目。我使用了
第一个
，但由于您可以获得mult，因此您的里程可能会有所不同iple项目；如果您确实获得了多个项目，您必须找出哪一个是合适的


下面是一些代码：

require 'json'
require 'open-uri'

imdb_id = 'tt0120338'
url = "http://mymovieapi.com/?id=#{ imdb_id }&type=json&plot=none&episode=0&lang=en-US&aka=simple&release=simple&business=0&tech=0"
doc = open(url).read
doc[0..5] # => "{\"rati"
json = JSON.parse(doc) # => {"rating_count"=>493949, "genres"=>["Drama", "Romance"], "rated"=>"PG-13", "language"=>["English", "French", "German", "Swedish", "Italian", "Russian"], "rating"=>7.6, "country"=>["USA"], "release_date"=>19980403, "title"=>"Titanic", "year"=>1997, "filming_locations"=>"Santa Clarita, California, USA", "imdb_id"=>"tt0120338", "directors"=>["James Cameron"], "writers"=>["James Cameron"], "actors"=>["Leonardo DiCaprio", "Kate Winslet", "Billy Zane", "Kathy Bates", "Frances Fisher", "Gloria Stuart", "Bill Paxton", "Bernard Hill", "David Warner", "Victor Garber", "Jonathan Hyde", "Suzy Amis", "Lewis Abernathy", "Nicholas Cascone", "Anatoly M. Sagalevitch"], "also_known_as"=>["Tai tan ni ke hao"], "poster"=>{"imdb"=>"http://ia.media-imdb.com/images/M/MV5BMjExNzM0NDM0N15BMl5BanBnXkFtZTcwMzkxOTUwNw@@._V1_SY317_CR0,0,214,317_.jpg", "cover"=>"http://imdb-poster.b0.upaiyun.com/000/120/338.jpg!cover?_upt=7dedce781382606097"}, "runtime"=>["194 min"], "type"=>"M", "imdb_url"=>"http://www.imdb.com/title/tt0120338/"}
json["imdb_id"] # => "tt0120338"

这返回了一个作为JSON响应的项目。通过查看
doc
变量可以看到它是JSON，而不是HTML。使用JSON解析器解析它返回了一个哈希

url = "http://mymovieapi.com/?title=#{ json['title'] }&type=json&plot=simple&episode=0&limit=1&year=#{ json['year'] }&yg=1&mt=none&lang=en-US&offset=&aka=simple&release=simple&business=0&tech=0"
doc = open(url).read
doc[0..5] # => "[{\"rat"
json = JSON.parse(doc).first # => {"rating_count"=>493949, "genres"=>["Drama", "Romance"], "rated"=>"PG-13", "language"=>["English", "French", "German", "Swedish", "Italian", "Russian"], "rating"=>7.6, "country"=>["USA"], "release_date"=>19980403, "title"=>"Titanic", "year"=>1997, "filming_locations"=>"Santa Clarita, California, USA", "imdb_id"=>"tt0120338", "directors"=>["James Cameron"], "writers"=>["James Cameron"], "actors"=>["Leonardo DiCaprio", "Kate Winslet", "Billy Zane", "Kathy Bates", "Frances Fisher", "Gloria Stuart", "Bill Paxton", "Bernard Hill", "David Warner", "Victor Garber", "Jonathan Hyde", "Suzy Amis", "Lewis Abernathy", "Nicholas Cascone", "Anatoly M. Sagalevitch"], "plot_simple"=>"A seventeen-year-old aristocrat, expecting to be married to a rich claimant by her mother, falls in love with a kind but poor artist aboard the luxurious, ill-fated R.M.S. Titanic.", "poster"=>{"imdb"=>"http://ia.media-imdb.com/images/M/MV5BMjExNzM0NDM0N15BMl5BanBnXkFtZTcwMzkxOTUwNw@@._V1_SY317_CR0,0,214,317_.jpg", "cover"=>"http://imdb-poster.b0.upaiyun.com/000/120/338.jpg!cover?_upt=7dedce781382606097"}, "runtime"=>["194 min"], "type"=>"M", "imdb_url"=>"http://www.imdb.com/title/tt0120338/", "also_known_as"=>["Tai tan ni ke hao"]}
json["imdb_id"] # => "tt0120338"

此请求返回了一个合理的哈希数组。JSON字符串是一个数组，在
doc
变量中可见。对其进行解析，然后仅获取第一个元素，就可以读取
imdb\u id
的值

请再次注意，这里不涉及HTML解析器，也不需要HTML解析器。您必须查看要返回的数据，而不仅仅是假设。
是“put json[“imdb_id”]”还是“puts”？你能发布为第二种类型返回的json吗？@AmithKoujalgi这是puts，我在这里输入了那个小部分，犯了一个错误。我复制了第二个json输出，但它完全相同。你为什么要使用Hpricot？为什么要使用Hpricot“解析”收到的JSON输出？首先，它不是必需的，它也被Nokogiri取代，因此，如果你需要解析HTML，而你不需要，你最好使用一个更新的HTML解析器。@theTinMan我对JSON相当陌生（这是我第一个使用它的真正应用程序），所以谢谢你的提醒。我不确定如何从网页中获取JSON，我在其他地方使用了Hpricot，所以我用它来实现。我应该怎么做？使用Nokogiri，或者其他方式？不要使用Nokogiri或Hpricot。你请求的是JSON响应，这就是你得到的。我不认为这是一个数组。
puts[1]
将输出与
放置1
相同的内容（
1
）因为它将输出由新行分隔的每个元素。根据问题中给出的输出，不可能知道json是显示的哈希还是实际包含显示的哈希的数组。Andrew应该检查
json.class
或
json.inspect
第二个json响应返回一个数组。第一个是：
doc[0..5]#=>“{\”rati”
第二个：
doc[0..5]#=>“[{\”rat”
。
url = "http://mymovieapi.com/?title=#{ json['title'] }&type=json&plot=simple&episode=0&limit=1&year=#{ json['year'] }&yg=1&mt=none&lang=en-US&offset=&aka=simple&release=simple&business=0&tech=0"
doc = open(url).read
doc[0..5] # => "[{\"rat"
json = JSON.parse(doc).first # => {"rating_count"=>493949, "genres"=>["Drama", "Romance"], "rated"=>"PG-13", "language"=>["English", "French", "German", "Swedish", "Italian", "Russian"], "rating"=>7.6, "country"=>["USA"], "release_date"=>19980403, "title"=>"Titanic", "year"=>1997, "filming_locations"=>"Santa Clarita, California, USA", "imdb_id"=>"tt0120338", "directors"=>["James Cameron"], "writers"=>["James Cameron"], "actors"=>["Leonardo DiCaprio", "Kate Winslet", "Billy Zane", "Kathy Bates", "Frances Fisher", "Gloria Stuart", "Bill Paxton", "Bernard Hill", "David Warner", "Victor Garber", "Jonathan Hyde", "Suzy Amis", "Lewis Abernathy", "Nicholas Cascone", "Anatoly M. Sagalevitch"], "plot_simple"=>"A seventeen-year-old aristocrat, expecting to be married to a rich claimant by her mother, falls in love with a kind but poor artist aboard the luxurious, ill-fated R.M.S. Titanic.", "poster"=>{"imdb"=>"http://ia.media-imdb.com/images/M/MV5BMjExNzM0NDM0N15BMl5BanBnXkFtZTcwMzkxOTUwNw@@._V1_SY317_CR0,0,214,317_.jpg", "cover"=>"http://imdb-poster.b0.upaiyun.com/000/120/338.jpg!cover?_upt=7dedce781382606097"}, "runtime"=>["194 min"], "type"=>"M", "imdb_url"=>"http://www.imdb.com/title/tt0120338/", "also_known_as"=>["Tai tan ni ke hao"]}
json["imdb_id"] # => "tt0120338"