Ruby-on-rails – Loop over Object attributes in Ruby on Rails

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Is it possible to loop over an object's attributes in Rails? I have an object and rather than code up each attribute in the view, I want to output each of them in the view as there are quite a few.

I have an object called @work_profile which has many attributes, mainly boolean check box values.

Edit: I see I can use @work_profile.attributes. Any help on formatting the hash into something more user friendly would be great.

Best Solution

The ActiveRecord::Base.attributes() method returns a hash of all the attributes. You can use that to loop over all attributes.

@work_profile.attributes.each do |attr_name, attr_value|
  ...
end

In a view, this would give:

<% @work_profile.attributes.each do |attr_name, attr_value| %>
  <div class="work_profile_attribute">
    <%= attr_name %>: <%= attr_value %>
  </div>
<% end %>

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Ruby-on-rails – How to “pretty” format JSON output in Ruby on Rails

Use the pretty_generate() function, built into later versions of JSON. For example:

require 'json'
my_object = { :array => [1, 2, 3, { :sample => "hash"} ], :foo => "bar" }
puts JSON.pretty_generate(my_object)

Which gets you:

{
  "array": [
    1,
    2,
    3,
    {
      "sample": "hash"
    }
  ],
  "foo": "bar"
}

Ruby-on-rails – How to get a random number in Ruby

Use rand(range)

From Ruby Random Numbers:

If you needed a random integer to simulate a roll of a six-sided die, you'd use: 1 + rand(6). A roll in craps could be simulated with 2 + rand(6) + rand(6).

Finally, if you just need a random float, just call rand with no arguments.

As Marc-André Lafortune mentions in his answer below (go upvote it), Ruby 1.9.2 has its own Random class (that Marc-André himself helped to debug, hence the 1.9.2 target for that feature).

For instance, in this game where you need to guess 10 numbers, you can initialize them with:

10.times.map{ 20 + Random.rand(11) } 
#=> [26, 26, 22, 20, 30, 26, 23, 23, 25, 22]

Note:

Using Random.new.rand(20..30) (using Random.new) generally would not be a good idea, as explained in detail (again) by Marc-André Lafortune, in his answer (again).
But if you don't use Random.new, then the class method rand only takes a max value, not a Range, as banister (energetically) points out in the comment (and as documented in the docs for Random). Only the instance method can take a Range, as illustrated by generate a random number with 7 digits.

This is why the equivalent of Random.new.rand(20..30) would be 20 + Random.rand(11), since Random.rand(int) returns “a random integer greater than or equal to zero and less than the argument.” 20..30 includes 30, I need to come up with a random number between 0 and 11, excluding 11.

Best Solution

Related Solutions

Ruby-on-rails – How to “pretty” format JSON output in Ruby on Rails

Ruby-on-rails – How to get a random number in Ruby

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