Ruby 在散列数组中轻松搜索键值对
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Ruby easy search for key-value pair in an array of hashes
提问by Brian Weinreich
Suppose I have this array of hashes:
假设我有这个哈希数组：
[
{"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"
如何解析散列的“ href”值，其中“product”=>“bcx”
Is there any easy way to do this in Ruby?
有没有什么简单的方法可以在 Ruby 中做到这一点？
回答by Niklas B.
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:
请注意，这仅在元素存在时才有效。否则，您将调用订阅运算符[]on nil，这将引发异常，因此您可能需要先检查：
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:
如果您需要多次执行该操作，您应该为自己构建一个数据结构以加快查找速度：
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"
