CODEWITHSUNDEEP
rubyhash
Markus Berg
Markus Berg

Reputation: 341

Create hash in ruby instantly

I was searching on the internet for some easy interpretation of hashes in ruby but I haven`t found (let me know if you found). Thing is I am looking for a nice and efficient way to create hash values on the go. Here is my current example:

home = {}
home['rooms'] = {}
home['rooms']['kitchen'] = 'this is kitchen'
home['rooms']['hall'] = 'welcome in hall'

But this is really long interpretation. I am searching something similar in ruby to this:

home = {}
home['rooms']['kitchen'] = 'this is kitchen'
home['rooms']['kitchen']['some_parameter']['some_parameter2'] = 'random text'

I don`t want to define hash on the each step.

home['rooms'] = {}
home['rooms']['kitchen'] = {}
home['rooms']['kitchen']['some_parameter'] = {}

I hope it was clear what is my intent, if not I will answer in comments. During my code I would like to define new hashes. I don`t know the structure before, so idea is when I create new var[p1][p2][p3] it will be automatically created as hash and it it will not produce an error.

The thing is, those hashes keys can be created dynamically, from variable.

Upvotes: 1

Views: 429

Answers (2)

Stefan
Stefan

Reputation: 114248

You can create a hash which uses another hash as its default value:

home = Hash.new { |h, k| h[k] = Hash.new(&h.default_proc) }

home['rooms']['kitchen'] = 'this is kitchen'
home['rooms']['hall'] = 'welcome in hall'

home
#=> {"rooms"=>{"kitchen"=>"this is kitchen", "hall"=>"welcome in hall"}}

Passing default_proc on to the inner hash ensures that you can nest it indefinitely:

home['foo']['bar']['baz'] = 'qux'

home
#=> {"rooms"=>{"kitchen"=>"this is kitchen", "hall"=>"welcome in hall"},
#    "foo"=>{"bar"=>{"baz"=>"qux"}}}

Upvotes: 3

gr33nTHumB
gr33nTHumB

Reputation: 368

You can pass the entire hash (if you know the keys you want) when you instantiate the first one.

Something like this: 

home = { 
  rooms: {  
    kitchen: '',
    hall: ''
  } 
}

home[:rooms][:kitchen] = 'this is kitchen'
home[:rooms][:hall] = 'welcome in hall'

If you already have the values: 

home = { 
  rooms: {  
    kitchen: 'this is kitchen',
    hall: 'welcome in hall'
  } 
}

If you could provide a use case example, that would probably enable more precise answers.

EDIT: If you want to access your keys with either String or Symbol:

home = { 
  rooms: {  
    kitchen: 'this is kitchen',
    hall: 'welcome in hall'
  } 
}.with_indifferent_access

Upvotes: 0

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