CODEWITHSUNDEEP
ruby
Nicholas Alek
Nicholas Alek

Reputation: 273

Convert an Array of Strings to a Hash in Ruby

I have an Array that contains strings:

["First Name", "Last Name", "Location", "Description"]

I need to convert the Array to a Hash, as in the following:

{"A" => "First Name", "B" => "Last Name", "C" => "Location", "D" => "Description"}

Also, this way too:

{"First Name" => "A", "Last Name" => "B", "Location" => "C", "Description" => "D"}

Any thoughts how to handle this the best way?

Upvotes: 0

Views: 204

Answers (4)

Cary Swoveland
Cary Swoveland

Reputation: 110675

You could do this:

arr = ["First Name", "Last Name", "Location", "Description"]

letter = Enumerator.new do |y|
  l = ('A'.ord-1).chr
  loop do
    y.yield l=l.next
  end
end
  #=> #<Enumerator: #<Enumerator::Generator:0x007f9a00878fd8>:each> 

h = arr.each_with_object({}) { |s,h| h[letter.next] = s }
  #=> {"A"=>"First Name", "B"=>"Last Name", "C"=>"Location", "D"=>"Description"} 

h.invert
  #=> {"First Name"=>"A", "Last Name"=>"B", "Location"=>"C", "Description"=>"D"}

or

letter = ('A'.ord-1).chr
  #=> "@" 
h = arr.each_with_object({}) { |s,h| h[letter = letter.next] = s }
  #=> {"A"=>"First Name", "B"=>"Last Name", "C"=>"Location", "D"=>"Description"}

When using the enumerator letter, we have

27.times { puts letter.next }
  #=> "A"
  #   "B"
  #   ...
  #   "Z"
  #   "AA"

Upvotes: 1

Oleksandr Holubenko
Oleksandr Holubenko

Reputation: 4440

Or..You also can try this :)

letter = 'A'
arr = ["First Name", "Last Name", "Location", "Description"]
hash = {}
arr.each { |i|
hash[i] = letter
letter = letter.next
}

// => {"First Name"=>"A", "Last Name"=>"B", "Location"=>"C", "Description"=>"D"}

or

letter = 'A'
arr = ["First Name", "Last Name", "Location", "Description"]
hash = {}
arr.each { |i|
hash[letter] = i
letter = letter.next
}

// => {"A"=>"First Name", "B"=>"Last Name", "C"=>"Location", "D"=>"Description"}

Upvotes: 0

Hare Kumar
Hare Kumar

Reputation: 719

If you are not being specific about keys name then you could try this out

 list = ["First Name", "Last Name", "Location", "Description"] 
 Hash[list.map.with_index{|*x|x}].invert

Output

 {0=>"First Name", 1=>"Last Name", 2=>"Location", 3=>"Description"}

Similar solutions is here.

Upvotes: 0

engineersmnky
engineersmnky

Reputation: 29328

You could implement as follows 

 def string_array_to_hash(a=[],keys=false)
    headers = ("A".."Z").to_a
    Hash[keys ? a.zip(headers.take(a.count)) : headers.take(a.count).zip(a)]
 end

Then to get your initial output it would be 

 a = ["First Name", "Last Name", "Location", "Description"]
 string_array_to_hash a 
 #=> {"A"=>"First Name", "B"=>"Last Name", "C"=>"Location", "D"=>"Description"}

And second output is 

 a = ["First Name", "Last Name", "Location", "Description"]
 string_array_to_hash a, true 
 #=> {"First Name"=>"A", "Last Name"=>"B", "Location"=>"C", "Description"=>"D"}

Note: this will work as long as a is less than 27 Objects otherwise you will have to specify a different desired output. This is due to the fact that a) the alphabet only has 26 letters b) Hash objects can only have unique keys.

Upvotes: 2

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