Sorting array of hashes based on multiple values

Question

I have an array of hashes:

[ 
  {
    :title=>"Working as a SSE",
    :organisation=>{:id=>428, :name=>"google"},
    :from=>"2018-6-1",
    :to=>nil
  }, {
    :title=>"Concatenate two video files to single video in players",
    :organisation=>{:id=>197, :name=>"UNFPA"},
    :from=>"2014-1-1",
    :to=>"2015-12-1"
  }, {
    :title=>"Highcharts Demo",
    :organisation=>{:id=>6, :name=>"UNDFS"},
    :from=>"2016-1-1",
    :to=>"2017-6-1"
  }, {
    :title=>"Working as a Judicial Affairs",
    :organisation=>{:id=>427, :name=>"swtp"},
    :from=>"2017-1-1",
    :to=>"2018-6-1"
  }
]

I want to sort it in the following order:

1. First sort is based on to
2. Second sort is based on from
3. Third sort is based on organisation name
4. Finally, sort based on title

Can anyone help me sort the array of hashes?

Answer 1

arr = [ 
  {
    :title=>"Working as a SSE",
    :organisation=>{:id=>428, :name=>"google"},
    :from=>"2018-6-1",
    :to=>"2017-6-1"
  }, {
    :title=>"Concatenate two video files to single video in players",
    :organisation=>{:id=>197, :name=>"UNFPA"},
    :from=>"2014-1-1",
    :to=>"2015-12-1"
  }, {
    :title=>"Highcharts Demo",
    :organisation=>{:id=>6, :name=>"UNDFS"},
    :from=>"2016-1-1",
    :to=>"2017-6-1"
  }, {
    :title=>"Working as a Judicial Affairs",
    :organisation=>{:id=>427, :name=>"swtp"},
    :from=>"2017-1-1",
    :to=>"2018-6-1"
  }
]

arr.sort_by { |h| [h[:to], h[:from], h[:organisation][:name], h[:title]] }
  #=> [{:title=>"Concatenate two video files to single video in players",
  #     :organisation=>{:id=>197, :name=>"UNFPA"},
  #     :from=>"2014-1-1",
  #     :to=>"2015-12-1"},
  #    {:title=>"Highcharts Demo",
  #     :organisation=>{:id=>6, :name=>"UNDFS"},
  #     :from=>"2016-1-1",
  #     :to=>"2017-6-1"},
  #    {:title=>"Working as a SSE",
  #     :organisation=>{:id=>428, :name=>"google"},
  #     :from=>"2018-6-1",
  #     :to=>"2017-6-1"},
  #    {:title=>"Working as a Judicial Affairs",
  #     :organisation=>{:id=>427, :name=>"swtp"},
  #     :from=>"2017-1-1",
  #     :to=>"2018-6-1"}]

See Array#<=> , particularly the third paragraph of the doc, and Enumerable#sort_by .