如何在Rails中对哈希数组的所有值进行排序？ 蒙戈

Question

I have a controller action that grabs some information for me:

@account = Account.find(params[:id])
@acct_cust = Customer.all(:account_id => @account.id.to_s)
@acct_cust.each do |ac|
  @jobAc << Job.where(:customer_id => ac.id).sort(:start_date)
end

We have the account, then we grab all the customers who belong to this account, then we grab all the jobs of each customer and shove them into an array.

So what I want to do is sort that final array - @jobAc - by the :start_date value.

Of course I start with plucky queries shoved into this array as you see in the log:

Console log:

 jobAc is [#<MongoMapper::Plugins::Querying::DecoratedPluckyQuery customer_id:  
 BSON::ObjectId('52705ff24031a0000e000179'), sort: [["start_date", 1]], transformer:  
 #<Proc:0x007fe3e6f834d8@/usr/local/rvm/gems/ruby-2.0.0-p247/gems/mongo_mapper-0.13.0.beta2
 /lib/mongo_mapper/plugins/querying.rb:66 (lambda)>>, 
 #<MongoMapper::Plugins::Querying::DecoratedPluckyQuery customer_id: 
 BSON::ObjectId('5279795e2f6984000b00014f'), sort: [["start_date", 1]], transformer: 
 #<Proc:0x007fe3eb13b8f8@/usr/local/rvm/gems/ruby-2.0.0-p247/gems/mongo_mapper-0.13.0.beta2
 /lib/mongo_mapper/plugins/querying.rb:66 (lambda)>>, 
 #<MongoMapper::Plugins::Querying::DecoratedPluckyQuery customer_id: 
 BSON::ObjectId('52797beb2f698400ef0000c4'), sort: [["start_date", 1]], transformer: 
 #<Proc:0x007fe3e9da35e8@/usr/local/rvm/gems/ruby-2.0.0-p247/gems/mongo_mapper-0.13.0.beta2
 /lib/mongo_mapper/plugins/querying.rb:66 (lambda)>>, 
 #<MongoMapper::Plugins::Querying::DecoratedPluckyQuery customer_id: 
 BSON::ObjectId('527dac2d3d126f0107000059'), sort: [["start_date", 1]], transformer: 
 #<Proc:0x007fe3eb170cb0@/usr/local/rvm/gems/ruby-2.0.0-p247/gems/mongo_mapper-0.13.0.beta2
 /lib/mongo_mapper/plugins/querying.rb:66 (lambda)>>]

If I use @jobAc = Job.all(query) I end up with an array of the values like this:

[[{1},{2},{3}],[{1},{2}]]

I can't even understand the question I'm trying to ask properly :) Am I trying to flatten an array of hashes? I tried that but didn't come up with what I thought.

I tried :

@jobAc.sort_by!(&:start_date).reverse but this of course cannot be done while they are plucky queries instead of the actual values.

Any ideas?

Answer 1

The issue here is that you're selecting only parts of your dataset at a time in a loop, rather than sorting the whole dataset.

You can improve the runtime of this code and apply the sort by performing a single query to find all your jobs, with a sort parameter:

@account = Account.find(params[:id])
@acct_cust = Customer.all(:account_id => @account.id.to_s)
@jobAc = Job.where(:customer_id.in => @acct_cust.map(:id)).sort(:start_date)

Since you're using MongoMapper, I'd recommend that you use associations and scopes:

class Account
  many :customers
end

class Customer
  belongs_to :account
end

class Job
  scope :for_account, ->(account) do
    where(:customer_id.in => account.customers.fields(:id).all.map(:id))
  end
end

Then you can just find all the jobs for a given customer:

@jobAc = Job.for_account( Account.find(params[:id]) )