这对于普通哈希来说很简单
{:a => "a", :b => "b"}
这就意味着
"a=a&b=b"
但是你怎么处理更复杂的东西，比如
{:a => "a", :b => ["c", "d", "e"]}
这应该转化为
"a=a&b[0]=c&b[1]=d&b[2]=e"
或者更糟的是，(该怎么做)像这样的事情:
{:a => "a", :b => [{:c => "c", :d => "d"}, {:e => "e", :f => "f"}]
非常感谢你的帮助!
当前回答
对于基本的、非嵌套的散列，Rails/ActiveSupport有object# to_query。
>> {:a => "a", :b => ["c", "d", "e"]}.to_query
=> "a=a&b%5B%5D=c&b%5B%5D=d&b%5B%5D=e"
>> CGI.unescape({:a => "a", :b => ["c", "d", "e"]}.to_query)
=> "a=a&b[]=c&b[]=d&b[]=e"
http://api.rubyonrails.org/classes/Object.html#method-i-to_query
其他回答
对于基本的、非嵌套的散列，Rails/ActiveSupport有object# to_query。
>> {:a => "a", :b => ["c", "d", "e"]}.to_query
=> "a=a&b%5B%5D=c&b%5B%5D=d&b%5B%5D=e"
>> CGI.unescape({:a => "a", :b => ["c", "d", "e"]}.to_query)
=> "a=a&b[]=c&b[]=d&b[]=e"
http://api.rubyonrails.org/classes/Object.html#method-i-to_query
{:a=>"a", :b=>"b", :c=>"c"}.map{ |x,v| "#{x}=#{v}" }.reduce{|x,v| "#{x}&#{v}" }
"a=a&b=b&c=c"
还有另一种方法。对于简单的查询。
更新:此功能已从gem中移除。
朱利安，你自己的回答很好，我无耻地借鉴了它，但它不能正确地逃脱保留字符，还有一些其他的边缘情况，它会崩溃。
require "addressable/uri"
uri = Addressable::URI.new
uri.query_values = {:a => "a", :b => ["c", "d", "e"]}
uri.query
# => "a=a&b[0]=c&b[1]=d&b[2]=e"
uri.query_values = {:a => "a", :b => [{:c => "c", :d => "d"}, {:e => "e", :f => "f"}]}
uri.query
# => "a=a&b[0][c]=c&b[0][d]=d&b[1][e]=e&b[1][f]=f"
uri.query_values = {:a => "a", :b => {:c => "c", :d => "d"}}
uri.query
# => "a=a&b[c]=c&b[d]=d"
uri.query_values = {:a => "a", :b => {:c => "c", :d => true}}
uri.query
# => "a=a&b[c]=c&b[d]"
uri.query_values = {:a => "a", :b => {:c => "c", :d => true}, :e => []}
uri.query
# => "a=a&b[c]=c&b[d]"
宝石是“可寻址的”
gem install addressable
如果使用Ruby 1.9.2或更高版本，则可以使用URI。Encode_www_form如果你不需要数组。
例如(来自1.9.3的Ruby文档):
URI.encode_www_form([["q", "ruby"], ["lang", "en"]])
#=> "q=ruby&lang=en"
URI.encode_www_form("q" => "ruby", "lang" => "en")
#=> "q=ruby&lang=en"
URI.encode_www_form("q" => ["ruby", "perl"], "lang" => "en")
#=> "q=ruby&q=perl&lang=en"
URI.encode_www_form([["q", "ruby"], ["q", "perl"], ["lang", "en"]])
#=> "q=ruby&q=perl&lang=en"
您会注意到，数组值不是用包含[]的键名来设置的，就像我们在查询字符串中习惯的那样。encode_www_form使用的规范与HTML5对application/x-www-form-urlencoded data的定义一致。
class Hash
def to_params
params = ''
stack = []
each do |k, v|
if v.is_a?(Hash)
stack << [k,v]
elsif v.is_a?(Array)
stack << [k,Hash.from_array(v)]
else
params << "#{k}=#{v}&"
end
end
stack.each do |parent, hash|
hash.each do |k, v|
if v.is_a?(Hash)
stack << ["#{parent}[#{k}]", v]
else
params << "#{parent}[#{k}]=#{v}&"
end
end
end
params.chop!
params
end
def self.from_array(array = [])
h = Hash.new
array.size.times do |t|
h[t] = array[t]
end
h
end
end
