選択リストの作成時にcontrollers.rbに構文エラーが出る。

Question

選択リストの作成時にcontrollers.rbに構文エラーが出る。

Controllers.rbの全文
class TikkaController < ApplicationController

def index
    if request.post? then
        @title = "Result"
        if params["s1"] then
            @msg = "you selected: " + "params["s1"]
        else
            @msg = "not selected..."
        end
    else
        @title = "index"
        @msg = "select List..."
    end
end

end

index.html.erbの全文

<h1><%= @title %></h1> <p><%= @msg %></p> <%= form_tag(controller: "tikka",action: "index") do %> <%= serect_tag("s1", options_for_select(["Windows", "macOS", "Linux"])) %> <%= submit_tag("Click") %> <% end %>

エラー全文
Started GET "/tikka" for 127.0.0.1 at 2017-11-01 22:43:40 +0900
C:/Users/Admin/Ruby22-x64/RailsApp/app/controllers/tikka_controller.rb:12: warning: string literal in condition

SyntaxError (C:/Users/Admin/Ruby22-x64/RailsApp/app/controllers/tikka_controller.rb:7: syntax error, unexpected tIDENTIFIER, expecting keyword_end
@msg = "you selected: " + "params["s1"]
^
C:/Users/Admin/Ruby22-x64/RailsApp/app/controllers/tikka_controller.rb:9: syntax error, unexpected keyword_not, expecting keyword_end
@msg = "not selected..."
^
C:/Users/Admin/Ruby22-x64/RailsApp/app/controllers/tikka_controller.rb:12: syntax error, unexpected tIDENTIFIER, expecting keyword_end
@title = "index"
^
C:/Users/Admin/Ruby22-x64/RailsApp/app/controllers/tikka_controller.rb:13: syntax error, unexpected tIDENTIFIER, expecting keyword_end
@msg = "select List..."
^
C:/Users/Admin/Ruby22-x64/RailsApp/app/controllers/tikka_controller.rb:13: unterminated string meets end of file
C:/Users/Admin/Ruby22-x64/RailsApp/app/controllers/tikka_controller.rb:13: syntax error, unexpected end-of-input, expecting keyword_end):

app/controllers/tikka_controller.rb:7: syntax error, unexpected tIDENTIFIER, expecting keyword_end
app/controllers/tikka_controller.rb:9: syntax error, unexpected keyword_not, expecting keyword_end
app/controllers/tikka_controller.rb:12: syntax error, unexpected tIDENTIFIER, expecting keyword_end
app/controllers/tikka_controller.rb:13: syntax error, unexpected tIDENTIFIER, expecting keyword_end
app/controllers/tikka_controller.rb:13: unterminated string meets end of file
app/controllers/tikka_controller.rb:13: syntax error, unexpected end-of-input, expecting keyword_end

Answer 1

コード部を選択して上の</>みたいなボタンを押してみてください。
そうするとわかります。

class TikkaController < ApplicationController
  
  def index
    if request.post? then
      @title = "Result"
      if params["s1"] then
        @msg = "you selected: " + "params["s1"]
      else
        @msg = "not selected..."
      end
    else
      @title = "index"
      @msg = "select List..."
    end
  end
  
end

こうすることで色が変わりどこからおかしいのかがわかりやすくなりましたよね？

@msg = "you selected: " + "params["s1"]

この行のparamsの前のダブルクォーテーションは不必要です。