About the symbol <%%> in Rails erb

What is <%%> / <% =%>

As I was working on the task, I couldn't understand the "<% =%>" that came up, and I did some research. I found a collection of notes, so I'll leave it as a memorandum.

It seems that you can embed Ruby code in an HTML file by enclosing it in <%%> <% =%> in a Rails .erb format file. (Erb = Abbreviation for Embedded Ruby).

For example, if you enter the code below


<% language = "Ruby" %>
 <P><%= language %>learn</P>

↓ Result


スクリーンショット 2020-11-05 23.20.13.png

It will be. In addition, the definition of the variable of "<% language =" Ruby "%>" is generally defined by the action.


 def top
   @language = Ruby


 <%= @language %>

How to use <% = form_for%>


  <%= form_for ('Model class instance') do |f| %>
Fill out the form
  <% end %>

↓ If you change it to a code


  <%= form_for (@user) do |f| %>
     <% f.text_field :name %>
     <% f.submit %>
  <% end %>

It's like that.


  <form class="top">
    <input name="">

However, <% = form_for%> is recommended because it can be written shorter and security is improved.

Reference article

Someone wrote about <%%> in more detail. Thank you very much. Meaning of symbols used in Rails erb

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