CODEWITHSUNDEEP
ruby-on-railsrubysortinghash
Seralto
Seralto

Reputation: 1076

Sort a hash by value inside other hash - Ruby on Rails

I have a hash that contains another hash inside and I need to sort as follow:

data = {
    "user": {
        "name": "John",
        "age": "36",
    },
    "company": "Terminal",
    "country": "Canada",
} 
{
    "user": {
        "name": "Mary",
        "age": "32",
    },
    "company": "Brasco",
    "country": "Italy",
}

Using this way I can sort without problem:

data.sort_by { |a| [a[:company], a[:country]] }

But in case "company" and "country" have the same value, I need to sort by a third option, the "name".

The case is that I need to use the function 'reverse' at the end (the example I posted is not the real situation, the real one is too big...lol).

So the result is sorting the name reversed too.

data.sort_by { |a| [a['company'], a['country'], a['user']['name']] }.reverse

I need the "company" and "country" sort in DESC and user.name sort by ASC.

Upvotes: 3

Views: 507

Answers (3)

Victor Moroz
Victor Moroz

Reputation: 9225

Possible way if you do it often:

class Reverser
  attr_reader :v

  def initialize(v)
    @v = v
  end

  def self.[](v)
    new(v)
  end

  def <=>(other)
    other.v <=> @v
  end
end

# Order by company DESC, country DESC, user.name ASC
data.sort_by { |a| [Reverser[a['company']], Reverser[a['country']], a['user']['name']] }

Upvotes: 0

engineersmnky
engineersmnky

Reputation: 29328

How about this 

data = [
{
 "user" => {
    "name" => 'John',
    "age" => "36",
  },
  "company" => "Terminal"
  "country" => "Canada"
},
{
"user" => {
    "name" => 'Mary',
    "age" => "32",
  },
  "company" => "Brasco",
  "country" => "Italy"
},
{
"user" => {
    "name" => 'Andre',
    "age" => "32",
  },
  "company" => "Brasco",
  "country" => "Italy"
}]


data.sort do |a,b| 
  sort_direction = [a['company'],a['country']] <=> [b['company'],b['country']]
  b['user']['name'] <=> a['user']['name'] if sort_direction == 0
end
#=>=> [{"user"=>{"name"=>"Mary", "age"=>"32"}, "company"=>"Brasco", "country"=>"Italy"}{"user"=>{"name"=>"Andre", "age"=>"32"},"company"=>"Brasco", "country"=>"Italy"},{"user"=>{"name"=>"John", "age"=>"36"}, "company"=>"Terminal","country"=>"Canada"}]

Upvotes: 0

Uri Agassi
Uri Agassi

Reputation: 37409

data.sort_by { |a| [a['company'], a['country'], a['user']['name']] }

When sort_by receives an array, it compares each element when the previous ones tie.

If you want to sort company ASC, country ASC, name ASC and then easily reverse it to company DESC, country DESC, name ASC you can do this:

sorted = data.group_by do |x| 
  [x['company'], x['country']] 
end.each do |k, v| 
  v.sort_by! { |x| x[:user][:name] } 
end.sort_by(&:first).map(&:last)

This creates an array of arrays, each internal array contains all the users in the company/country pair, sorted by name.

now to get the ASC option you should do:

sorted.flatten

and the reverse (where users are still ASC) you need to:

sorted.reverse.flatten

Upvotes: 2

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