Select specific key from hash in Ruby

Question

I have the following JSON which I convert to hash:

<%
  json = '{
    "speed": 50,
    "braking": 50,
    "time_on_task": 50
  }'
  json = JSON.parse(json)
%>

And currently I just loop through them and display them:

<ul>
  <% json.each do |t| %>
      <li><%= "<b>#{t.first.humanize}</b>: #{t.last}".html_safe %></li>
  <% end %>
</ul>

However I'd like to build a method that can pick an particular item by its key name. e.g. show_score(json, 'speed')

I tried:

def show_score(hash, key)
  hash.select { |k| k == key }
end

Which just returns: {"speed"=>50}

So I tried:

hash.select { |k, h| "<b>#{k.humanize}</b>: #{h}".html_safe if k == key }

But it returns the same...

How can I get to just return the string in the format I want if they key matches?

Ursus · Accepted Answer · 2017-05-12 11:25:55Z

3

def show_score(hash, key)
  "<b>#{key.humanize}</b>: #{hash[key]}"
end

And I'd change this

<%
  json = '{
    "speed": 50,
    "braking": 50,
    "time_on_task": 50
  }'
  json = JSON.parse(json)
%>

into

<%
  hash = {
    "speed" => 50,
    "braking" => 50,
    "time_on_task" => 50
  }
  json = hash.to_json
%>

answered May 12, 2017 at 11:10

Ursus

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1 Comment

Doing that just returns 50 when doing json['speed'] How do I print the string I want by passing the key?

Josh Brody · Accepted Answer · 2017-05-12 23:34:01Z

1

I think you're thinking too hard, or maybe I'm not understanding your question fully.

<ul>
  <% json.each do |k,v| %>
      <li><%= "<b>#{k.humanize}</b>: #{v}".html_safe %></li>
  <% end %>
</ul>

ps. using Enumerable#detect is so much faster than Enumerable#select.first

answered May 12, 2017 at 23:34

Josh Brody

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