Loop through array of hashes with rails

Question

So I am trying to grab all high schools and graduate schools from this array of hashes:

"education": [
    {
      "school": {
        "id": "110703012290674", 
        "name": "Kunskapsgymnasiet Malmö"
      }, 
      "year": {
        "id": "136328419721520", 
        "name": "2009"
      }, 
      "type": "High School"
    }, 
    {
      "school": {
        "id": "112812485399398", 
        "name": "Malmö University"
      }, 
      "year": {
        "id": "118118634930920", 
        "name": "2012"
      }, 
      "concentration": [
        {
          "id": "104076956295773", 
          "name": "Computer Science"
        }
      ], 
      "type": "Graduate School", 
      "classes": [
        {
          "id": "165093923542525", 
          "name": "Programmering", 
          "description": "Kursen fokuserar på metoder och tekniker vid utveckling av webbapplikationer med hjälp av HTML5."
        }
      ]
    }
  ],

Like this:

if auth["extra"]["raw_info"]["education"]  

        # hash/array element 0
        if auth["extra"]["raw_info"]["education"][0]["type"] == "High School" 
          user.highschool_name = auth["extra"]["raw_info"]["education"][0]["school"]["name"] if (!auth["extra"].blank? && !auth["extra"]["raw_info"]["education"][0]["school"].blank?)
          user.highschool_year = auth["extra"]["raw_info"]["education"][0]["year"]["name"] if (!auth["extra"].blank? && !auth["extra"]["raw_info"]["education"][0]["year"].blank?)

        elsif auth["extra"]["raw_info"]["education"][0]["type"] == "Graduate School"
          user.graduateschool_name = auth["extra"]["raw_info"]["education"][0]["school"]["name"] if (!auth["extra"].blank? && !auth["extra"]["raw_info"]["education"][0]["school"].blank?)
          user.graduateschool_year = auth["extra"]["raw_info"]["education"][0]["year"]["name"] if (!auth["extra"].blank? && !auth["extra"]["raw_info"]["education"][0]["year"].blank?)
        end

        # hash/array element 1 
        if auth["extra"]["raw_info"]["education"][1]["type"] == "High School"
          user.highschool_name = auth["extra"]["raw_info"]["education"][1]["school"]["name"] if (!auth["extra"].blank? && !auth["extra"]["raw_info"]["education"][1]["school"].blank?)
          user.highschool_year = auth["extra"]["raw_info"]["education"][1]["year"]["name"] if (!auth["extra"].blank? && !auth["extra"]["raw_info"]["education"][1]["year"].blank?)

        elsif auth["extra"]["raw_info"]["education"][1]["type"] == "Graduate School"        
          user.graduateschool_name = auth["extra"]["raw_info"]["education"][1]["school"]["name"] if (!auth["extra"].blank? && !auth["extra"]["raw_info"]["education"][1]["school"].blank?)
          user.graduateschool_year = auth["extra"]["raw_info"]["education"][1]["year"]["name"] if (!auth["extra"].blank? && !auth["extra"]["raw_info"]["education"][1]["year"].blank?)
        end
      end

Is there a more efficient way to do it, like a loop of somekind? Any great ideas?

Sergio Tulentsev · Accepted Answer · 2012-07-09 20:33:59Z

2

Yes, exactly, you should use a loop. Seems that you want something like this:

if edu = auth["extra"]["raw_info"]["education"]  
  edu.each do |e|
    if e["type"] == "High School" 
      user.highschool_name = e["school"]["name"] if (!auth["extra"].blank? && !e["school"].blank?)
      user.highschool_year = e["year"]["name"] if (!auth["extra"].blank? && !e["year"].blank?)
    elsif e["type"] == "Graduate School"
      user.graduateschool_name = e["school"]["name"] if (!auth["extra"].blank? && !e["school"].blank?)
      user.graduateschool_year = e["year"]["name"] if (!auth["extra"].blank? && !e["year"].blank?)
    end
  end
end

Update

Okay, here's even simpler version (based on tokland's suggestions).

if (auth["extra"]["raw_info"]["education"] || []).each do |e|

  nameprop, yearprop = if e["type"] == "High School"
    [:highschool_name, :highschool_year]
  elsif e["type"] == "Graduate School"
    [:graduateschool_name, :graduateschool_year]
  end

  user.send("#{nameprop}=", e["school"]["name"]) if !e["school"].blank?
  user.send("#{yearprop}=", e["year"]["name"]) if !e["year"].blank?
end

edited Jul 9, 2012 at 20:33

answered Jul 9, 2012 at 19:54

Sergio Tulentsev

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3 Comments

tokland Over a year ago

Sergio, this can be simplified further, auth["extra"].blank? is everywhere. Also, this saves two lines a one indentation level: (something || []).each { ... }. Also, isn't the logic the same except for the receiver object? this simplified it even more.

tokland Over a year ago

Since !extra.blank? is everywhere it can be moved up, and I am happy with Sergio's solution :-) @SHUMAcupcake: another question would be: that kind of code tend to show problems in the data model.

Sergio Tulentsev Over a year ago

@tokland: seems that we can delete !extra.blank? calls altogether. If we entered the loop, it's obviously not blank.

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