parsing facebook json in rails avoid error occurred while evaluating nil.[]

I am trying to parse a json returned from facebook. Now my idea is to get as much as detailks as possible from the facebook json. So I use like ( assume auth is parse json from facebook)

education_array = auth['extra']['user_hash']['education']
education_array.each do |edu|
       puts edu['school']['name']
       puts edu['type']
       puts edu['year']['name']
     end

Now the problem here is that some people might have added the school name but not the year. so obviously

edu['year']['name'] will throw error telling "error occurred while evaluating nil.[]" .

How do I avoid this ?

one way which I thought was puts edu['year']['name']||""

but this would still throw error in case 'year' itself doesn't exist . (it would avoid error in case 'name' isn't found )

I don't want the following solution : check if auth['extra'] 开发者_运维问答exists then check if auth['extra']['user_hash'] exists then check if auth['extra']['user_hash']['education'] exists then check if auth['extra']['user_hash']['education']['year']['name'] and so on..

I don't think using exception handling is a good way.

Any good way ?

Thank you

Use the && operator to check for nils.

education_array.each do |edu|
  puts edu['school'] && edu['school']['name']
  puts edu['type']
  puts edu['year'] && edu['year']['name']
end

By way of example:

edu = { 'school' => { 'name' => 'value' } }
edu['school'] && edu['school']['name'] # => 'value'

edu = { 'school' => { } }
edu['school'] && edu['school']['name'] # => nil

edu = { 'school' => { } }
edu['school'] && edu['school']['name'] # => nil