ruby-on-rails - 如何访问仅存在于众多属性中的 1 个属性中的哈希值？

Question

所以这个有点棘手。

我有一个如下所示的属性:

[22] pry(main)> n.media.meta_info[:response][:outputs]
=> [{"id"=>486,
  "url"=>"http://some-video.com/by-fire.mp4",
  "label"=>"webmp4",
  "state"=>"finished",
  "format"=>"mpeg4",
  "type"=>"standard",
  "frame_rate"=>30.06,
 {"id"=>488848287,
  "url"=>"http://some-video.com/by-fire.webm",
  "label"=>"webwebm",
  "state"=>"finished",
  "format"=>"webm",
  "type"=>"standard",
  "frame_rate"=>30.06,
 {"id"=>488848288,
  "url"=>"http://some-video.com/by-fire.ogv",
  "label"=>"webogv",
  "state"=>"finished",
  "format"=>"ogg",
  "type"=>"standard",
  "frame_rate"=>30.059,
 {"id"=>488848289,
  "url"=>
   "https://zencoder-temp-storage-us-east-1.s3.amazonaws.com/",
  "label"=>nil,
  "state"=>"finished",
  "format"=>"mpeg4",
  "type"=>"standard",
  "frame_rate"=>30.06,
  "thumbnails"=>
   [{"label"=>nil,
     "images"=>
      [{"dimensions"=>"56x100",
        "file_size_bytes"=>15142,
        "format"=>"PNG",
        "url"=>"https://some-video.s3.amazonaws.com/uploads/video/video_file/id/by-fire.png"}]}],
  "md5_checksum"=>nil}]

我正在尝试访问 thumbnails 信息，特别是缩略图的 URL。

不过我不知道怎么去那里。

当我尝试访问 thumbnails 的嵌套哈希键时，它不起作用:

[23] pry(main)> n.media.meta_info[:response][:outputs][:thumbnails]
TypeError: no implicit conversion of Symbol into Integer
from (pry):22:in `[]'

想法？

Answer 1

输出开头的[{表示返回的是一个数组。您首先需要在包含 thumbnails 键的数组中找到一个元素:

outputs = n.media.meta_info[:response][:outputs]
output_with_thumbnail = outputs.find { |elem| elem.keys.include?('thumbnails') }

然后继续这样:

output_with_thumbnail['thumbnails']