<% posts_in_year_or_with_tag(item).each_with_index.select {|e, i| i.even?}.map(&:first).each do |post| %> <%= render '/partials/_blog_preview.*', post: post %> <% end %>

<% posts_in_year_or_with_tag(item).each_with_index.reject {|e, i| i.even?}.map(&:first).each do |post| %> <%= render '/partials/_blog_preview.*', post: post %> <% end %>