How to obtain the same result as <%= var %> without the =? - ruby-on-rails

In the Rails views, I regularly find lines like:
<%= my_var %>
What if I had a slightly more complex situation and I needed to trigger the printing with plain code instead of <%= %>?
Example:
<% .....
puts my_var
%>
I guess is a silly question but bear with me, I'm a ruby beginner.

Look at documentation of ERB
In <% %> you put expressions that are not for printing out.
In <%= %> you put code for printing out.
Example:
<% if #cost < 10 %>
<b>Only <%= #cost %>!!!</b>
<% else %>
Call for a price, today!
<% end %>

You can use helper method which is much more cleaner.

Related

Ruby on rails - each do class?

<% consents_checkboxes.each do |checkbox| %>
<%= checkbox.html_safe %>
<% end %>
Hello there,
can i give them a class while looping through them? I can't get it to work and tried several different ways.
This is something I would like to achieve
<% consents_checkboxes.each do |checkbox| %>
<%= checkbox.html_safe, class: 'checkbox' %>
<% end %>
thank you
You can only do it with an element. What you want to do is:
<% consents_checkboxes.each do |checkbox| %>
<p class="checkbox"><%= checkbox.html_safe %></p>
<% end %>
Of course, you can use another element (span, div etc.).
What's on consents_checkboxes? You should provide more context when you ask for something...
It looks like you have strings with the html code, right? you will have to parse the string with something like nokogiri and add a class
<%= Nokogiri.parse(checkbox).add_class('checkbox') -%>
Or you could modify the process that generates that consents_checkboxes to include the class you need. Maybe there's better options, but with only that information it's really hard to tell.

Comments from post not displaying correctly in rails

Been trying to set up a regular blog in Ruby on Rails, and finally got the comment system to work within a post. However, when I loop through each comment and try to output the comment's title it displays this,
awef [#<Comment id: 6, title: "awef", link: nil, campaign_id: 5, user_id: 1, created_at: "2015-09-24 09:46:43", updated_at: "2015-09-24 09:46:43">]
Instead of just the title. How can I fix this?
The loop in your view should be something like this:
<% #blog.comments.each do |f| %>
<%= f.title %>
<% end %>
Please check you are using the right angular parenthesis (<%= %>) and not placing p puts or inspect commands inside them.
Edit:
Now that you show use the code, the problem is in the first angular parenthesis: should be <% not <%=. The first is for the logic, the latter to output erb code.
<% #blog.comments.each do |f| %> # remove "="
<%= f.title %>
<% end %>
<% ... %>: Executes the ruby code within the brackets
<%= ...%>: Executes the ruby code and show the executing result in webpage
Classic mistake, it's because you're using <%= ERB output tags for the .each loop. You can view more information on how to write correct ERB here.
You need to replace your <%= output tags with standard ERB tags <%:
<% #blog.comments.each do |f| %>
I was stung by that one myself when I was starting out.
The problem you have is probably the = in your each statement.
Try to use this:
<% #blog.comments.each do |f| %>
<%= f.title %>
<% end %>
Notice the removed = at <% #blog.comments.each do |f| %>
The reason is as the <%= %> always prints while <% %> only executes the code.

Rails instance variable join

This is so simple but it's been ages since I needed this.
I have the following code
<% #miniature.minisets.each do |miniset| %>
<%= link_to miniset.name, miniset %>
<% end %>
It outputs Minisetname Minisetname Minisetname etc
I want it to output Minisetname, Minisetname, Minisetname with commas.
I've tried to include .join(", ") but can't find the right place to put it. Do I also need to use .map instead of .each?
Ignominy.
Here's one way that ought to work:
<%= #miniature.minisets.map { |miniset| link_to miniset.name, miniset }.join(", ").html_safe %>

How do I run multiple lines of Ruby in html.erb file

I'm using Ruby on Rails and need to run a block of Ruby code in one of my html.erb files. Do I do it like this:
<% def name %>
<% name = username %>
<%= name %>
or like this:
<% def name
name = username %>
<%= name %>
Thanks for reading.
If you need extra functions in your view, you normally declare those inside a helper.
For each controller, if there is a helper it is automatically loaded. For instance, if you have a PeopleController, in the app/helpers folder, there should be a people_helper.rb, and it should look like this
module PeopleHelper
def name
#do something
username
end
end
Another, very clean alternative, is to use the Presenter pattern, but i think it is less common (unfortunately).
Otherwise, if you do need multiple lines of ruby code inside a erb view, which i try to avoid, i prefer the following style:
<%
counter_1 = 0
counter_2 = 1
do_some_more_prep_here
%>
<% #records.each do |rec|%>
<%# do something with the prepped date in each row %>
<% end %>
Also for me code indentation is more important than html indentation, so i will prefer something like
<table>
<% #rows.each do |row| %>
<tr>
<td><%= row.item1 %></td>
<% if row.some_test %>
<td><%= row.item2 %></td>
<% end %>
</tr>
<% end %>
</table>
But i am always very interested to hear different opinions in this matter.
It is unusual to define a method in an ERB file, so I recommend against it.
If you want to call a block like #each, you can do something like the following:
<% names.each do |name| %>
<%= name %>
<% end %>
Don't forget the <% end %>.
I can imagine someone needing it in one particular template (no point in creating a helper) to not duplicate html markup. That is, when resulting html page has a couple of similar blocks of html markup. Though, it can easily be abused (unreadable code).
<% def f1(a, b, c) %>
test: <%= a %>, <%= b %>, <%= c %>
<% end %>
<% f1(1, 2, 3) %>
<% f1(4, 5, 6) %>

How to output text in rthml without <%=variable%>

I've been looking around for a solution to this question for the last couple of days. It's a simple annoyance, but I hate not knowing how to do things...
Environment: Ruby, Rails, rhtml
The Problem: When I iterate a collection in rhtml I would like to reduce the number of <% %> and <%= %> tags I use. The following seems bloated:
Example
<% #products.each do |p| %>
<%= #p.name %>
<% end %>
EDIT: how do I exclude <%= %> inside of a block?
I would much rather do:
<% #products.each do |p|
puts #p.name
end %>
Certain situations could allow for use of either... However, I know that I could do this with jsp:
<% for(int i=0; i<10;i++){
System.out.print(i);
} %>
Thanks in advance for your input.
if you want to be less verbose look at haml, with your example it will be :
- #products.each do |p|
= #p.name
<% #products.each do |p|
_erbout << #p.name
end %>
_erbout is the default name of the variable that ERB (the class that's parsing your .rhtml template) uses to build its output. This is pretty ugly, and feels a bit hacky to me, but it works.
Use print instead of put.
Several other possibilities, depending on the context, if your view code seems too bloated:
Use partials. E.g.:
in your main file:
<%= render(:partial => "product", :collection => products) %>
and in the partial, just use:
<%= product.name %>
Now this seems contrived for a simple example such as this but assuming something more complex it abstracts away the looping and makes the code clearer.
Use helper methods
You could also try using something like haml to clean up the templates (along with helpers and partials).
You're going to have to use a <%= inside such a block. You can achieve the readability you want by using a <%= with a block:
<%= #products.map do |p|
p.name
end.join("\n") %>

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