Ruby-on-rails 在没有 <%= 的情况下在 ERB 中打印？
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Print in ERB without <%=?
提问by Cheng
Sometimes it's more convenient to print in <%%>. How to do it in Rails?
有时用<%%> 打印更方便。如何在 Rails 中做到这一点？
回答by Omar Qureshi
http://api.rubyonrails.org/classes/ActionView/Helpers/TextHelper.html#method-i-concat
http://api.rubyonrails.org/classes/ActionView/Helpers/TextHelper.html#method-i-concat
Should be what you are looking for.
应该是你要找的。
E.g. the following statement using concat:
例如以下语句使用concat：
<% concat "Output" %>
is equivalent to:
相当于：
<%= "Output" %>
回答by Evolve
In ERB: The <% %> signify that there is Ruby code here to be interpreted. The <%= %> says output the ruby code, ie display/print the result.
在 ERB 中： <% %> 表示这里有 Ruby 代码需要解释。<%= %> 表示输出 ruby 代码，即显示/打印结果。
So it seems you need to use the extra = sign if you want to output in a standard ERB file.
因此，如果要在标准 ERB 文件中输出，似乎需要使用额外的 = 符号。
Otherwise, you could look at alternatives to ERB which require less syntax,.. maybe try something like HAML. http://haml-lang.com/tutorial.html
否则，您可以查看需要较少语法的 ERB 替代方案，.. 可以尝试使用 HAML 之类的方法。http://haml-lang.com/tutorial.html
Example:
# ERB
<strong><%= item.title %></strong>
# HAML
%strong= item.title
Is that more convenient?
这样更方便吗？
回答by brianegge
erbhas two method to evaluate inline ruby expressions. The <%which evaluates the expression and the <%=which evaluates and prints. There is no global object to print to within the binding context.
erb有两种方法来评估内联 ruby 表达式。在<%该计算表达式和<%=其评估和打印。在绑定上下文中没有要打印到的全局对象。
As mentioned by Omar, there is a concatmethod, which is part of ActionView. This will do what you want.
正如 Omar 所提到的，有一个concat方法，它是 ActionView 的一部分。这会做你想做的。
Unlike a scripting language escape, there is no default output for erb. Since erb is simply a function, and given a template and binding will return a variable, it returns the values of text and functions recursively.
与脚本语言转义不同，erb 没有默认输出。由于 erb 只是一个函数，并且给定模板和绑定将返回一个变量，因此它递归地返回文本和函数的值。
There is hot debate as to how much logic should be allowed in a view, but as little as possibleis what most people aim for. If you are putting more code than text in the view, you may want to consider refactoring your code.
关于视图中应该允许多少逻辑存在激烈争论，但尽可能少是大多数人的目标。如果您在视图中放置的代码多于文本，您可能需要考虑重构您的代码。
