I've fixed this problem by creating another helper method. "get_value" method will take collection and hidden value of the field and return the visible value. Collection is first converted into a Hash and then passing the hidden value to index operator returns visible value. Following is the code for us_states similarly any collection can be passed to this method to get visible value:
profiles_helper.rb
def us_states
[
['Alabama', 'AL'],
['Alaska', 'AK'],
['Arizona', 'AZ']
]
end
def get_value(collection, hidden_value)
hash = Hash[collection.map {|key, value| [value, key]}]
hash[hidden_value]
end
_form.html.erb
<%= simple_form_for(@profile) do |f| %>
<%= f.input :state, collection: us_states %>
<% end %>
show.html.erb
<%= get_value(us_states, @profile.state %>