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Ruby

Posted by Lawrence Chang
Lawrence Chang
4,659 Points

Populate hash with array keys and default value

The question asked was: Complete the solution so that it takes an array of keys and a default value and returns a hash with all keys set to the default value.

def solution(keys, default_value)
  hash = Hash.new
  keys.each { |k| hash[k] = default_value }
  hash
end

keys.each { |k| hash[k] = default_value }

Can someone explain what hash[k] = default_value does in the iteration. Thank you!

3 Answers

Nick Fuller
Nick Fuller
9,027 Points
Nick Fuller
Nick Fuller
9,027 Points

Hi Lawrence!

Remember you can access the value of a hash by calling it's key right? Like so

Given I have the following hash...

hash = { 'age' => 30, 'first_name' => 'Nick' }

When I pass a key to it with the [] syntax I wan to get the value for that key

hash['age']
=> 30

Likewise we can use the same mechanism to create a new key, value pair into the hash

Given I have the same hash as above

When a pass a value to the [] syntax with a new key I can set it's value; just like creating a normal variable

hash['last_name'] = 'Fuller'
=> "Fuller"

Now using the same logic above I can get that new value from that key

hash['last_name']
=> "Fuller"

And if we look at the entire hash we have

hash
=> {"age"=>30, "first_name"=>"Nick", "last_name"=>"Fuller"}

So your method would work like this...

candy = ["Skittles", "Starbursts", "Tacos"]

solution(candy, "$0.99")

=> { "Skittles" => "$0.99", "Starbursts" => "$0.99", "Tacos" => "$0.99" }
Lawrence Chang
Lawrence Chang
4,659 Points
Lawrence Chang
Lawrence Chang
4,659 Points

nick you are freaking awesome! thank you!