在哈希数组的Ruby容易寻找键值对 [英] Ruby easy search for key-value pair in an array of hashes

问题描述

假设我有此数组哈希的：

  [
{的href=＆gt;中https://company.campfirenow.com，名= GT;本公司，ID=＆GT; 123456789，产品= GT;篝火}，
{的href=＆gt;中https://basecamp.com/123456789/api/v1，名= GT;本公司，ID=＆GT; 123456789，产品= GT;BCX }，
{的href=＆gt;中https://company.highrisehq.com，名= GT;本公司，ID=＆GT; 123456789，产品= gt;中高层}
]
 

我如何解析的href 的哈希值，其中产品=>BCX

有没有简单的方法在Ruby中做到这一点？

解决方案

 元= [
  {的href=＆gt;中https://company.campfirenow.com，名= GT;本公司，ID=＆GT; 123456789，产品= GT;篝火}，
  {的href=＆gt;中https://basecamp.com/123456789/api/v1，名= GT;本公司，ID=＆GT; 123456789，产品= GT;BCX }，
  {的href=＆gt;中https://company.highrisehq.com，名= GT;本公司，ID=＆GT; 123456789，产品= gt;中高层}
]p {ary.find | H | H ['产品'] =='BCX'} ['href属性]
＃=＆GT; https://basecamp.com/123456789/api/v1
 

请注意，如果元素存在，这仅适用。否则，你将被调用认购运营商 [] 在无，这将引发异常，所以你可能要检查，首先：

 如果h = {ary.find | H | H ['产品'] =='BCX'}
  P H ['href属性]
其他
  把不存在！
结束
 

如果您需要执行该操作多次，你应该建立自己更快的查找数据结构：

  href_by_product =哈希[ary.map {| H | h.values​​_at（产品，HREF'）}]
p href_by_product ['篝火']＃=＆GT; https://company.campfirenow.com
p href_by_product ['BCX']＃=＆GT; https://basecamp.com/123456789/api/v1
 

Suppose I have this array of hashes:

[
{"href"=>"https://company.campfirenow.com", "name"=>"Company", "id"=>123456789, "product"=>"campfire"},
{"href"=>"https://basecamp.com/123456789/api/v1", "name"=>"Company", "id"=>123456789, "product"=>"bcx"}, 
{"href"=>"https://company.highrisehq.com", "name"=>"Company", "id"=>123456789, "product"=>"highrise"}
]

How can I parse the "href" value of the hash where "product"=>"bcx"

Is there any easy way to do this in Ruby?

解决方案

ary = [
  {"href"=>"https://company.campfirenow.com", "name"=>"Company", "id"=>123456789, "product"=>"campfire"},
  {"href"=>"https://basecamp.com/123456789/api/v1", "name"=>"Company", "id"=>123456789, "product"=>"bcx"}, 
  {"href"=>"https://company.highrisehq.com", "name"=>"Company", "id"=>123456789, "product"=>"highrise"}
]

p ary.find { |h| h['product'] == 'bcx' }['href']
# => "https://basecamp.com/123456789/api/v1"

Note that this only works if the element exists. Otherwise you will be calling the subscription operator [] on nil, which will raise an exception, so you might want to check for that first:

if h = ary.find { |h| h['product'] == 'bcx' }
  p h['href']
else
  puts 'Not found!'
end

If you need to perform that operation multiple times, you should build yourself a data structure for faster lookup:

href_by_product = Hash[ary.map { |h| h.values_at('product', 'href') }]
p href_by_product['campfire'] # => "https://company.campfirenow.com"
p href_by_product['bcx']      # => "https://basecamp.com/123456789/api/v1"

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