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Ruby

Sophie Rae
Sophie Rae
3,066 Points
Posted by Sophie Rae
Sophie Rae
3,066 Points

Create a String for values within a given Range from a Hash

Hi! Would be great if someone could give me a hand with solving this problem. I am not sure how to start...Thanks in advance!

Instructions:

Complete the solution so that it returns a String in the format:

"Key (Value), Key (Value)"

From a hash for values within the given range, sorted by value lowest to highest.

For example:

food = {
  "Hamburger"=>1.99,
  "Cheese"=>0.99,
  "Steak"=>4.99,
  "Lobster"=>7.99,
  "Fries"=>1.49,
  "Sandwich"=>2.49
}

list_in_range(food, (0.99..1.99)) # should return "Cheese (0.99), Fries (1.49), Hamburger (1.99)"

Your solution:

def list_in_range(hash, range)

end

1 Answer

Steve Hunter
Steve Hunter
57,712 Points

Hi Sophie,

Here's my attempt at that.

I'm sure there are far more elegant ways of manipulating hashes than this, though.

I set up the defined range, an empty hash and an empty string. Then, I've iterated through the food hash, pulling out the key and value (k and v) for each pair. Then, using the cover? method on the defined range, I pulled out the pairs where the value was within the range. This pair gets added to the empty hash. Then I reorder the hash and loop through it to create an interpolated string to look like your output.

I hope that's what you need. :smile:

Steve. 

food = {
  "Hamburger" => 1.99,
  "Cheese" => 0.99,
  "Steak" => 4.99,
  "Lobster" => 7.99,
  "Fries" => 1.49,
  "Sandwich" => 2.49
}

price_range = (0.99..1.99)

def list_in_range(food, price_range)
  out_hash = {}
  out_string = ""
  food.each do |k, v|
    if price_range.cover?(v)
      out_hash.store(k, v)  
    end
  end
  out_hash = out_hash.sort_by { | _key, value | value }
  out_hash.each do |k, v|
    out_string += "#{k} #{v}, "
  end
  puts out_string
end

# call the method
list_in_range(food, price_range)
Sophie Rae
Sophie Rae
3,066 Points
Sophie Rae
Sophie Rae
3,066 Points

Hi Steve!

Thanks very much for this. Can I ask what the cover? method does?

Sophie

Steve Hunter
Steve Hunter
57,712 Points

Hi Sophie,

The cover? method works on a Range object and returns true or false if the parameter passed in is within the range. Documentation is here.

I iterated over the food hash with an each loop. I pulled out the key and value with each iteration; I called them k and v. To determine if the hash item needed to be in the output hash, i.e. the item was within the price_range, I passed the value v into cover?. If I get true back, I added the key and value into out_hash using its store method

Steve. .