Question

Let’s say I have the following array of hashes:

h = [{"name" => "bob"}, {"car" => "toyota"}, {"age" => "25"}]

And I have the following key to match:

k = 'car'

How do I match the ‘k’ to ‘h’ and have delete every element after the match so that it returns:

h = [{"name" => "bob"}, {"car" => "toyota"}]

Answer 1

I like megas’ version, as its short and to the point. Another approach, which would be more explicit, would be iterating over the keys array of each hash. The keys of a hash are maintained in an ordered array (http://ruby-doc.org/core-1.9.3/Hash.html). They are ordered by when they were first entered. As a result, you can try the following:

newArray = Array.new
h.each do |hash| # Iterate through your array of hashes
    newArray << hash
    if hash.has_key?("car") # check if this hash is the "car" hash.
      break # exits the block
    end
end

This all depends, of course, on whether the array was created in the proper order. If it was, then you’re golden.