I have a view that for some reason displays the memory location of the object I'm trying to loop through. I'm kinda new at rails, so I'm unsure why this is happening. The object is a note with two fields, title and content.
In the controller I have (in the index function)
#note = Note.all
Then in the view I'm doing this
<%= #notes.each do |note| %>
<%= link_to note.title, "notes/#{note.id}"%>
<% end %>
The output in the browser is
School Work #Note:0x1042e4708>#Note:0x1042e2ae8>
Thanks for the help
rather than:
<%= #notes.each do |note| %>
use:
<% #notes.each do |note| %>
wrapping ruby in <%=%> will always output something to the view, drop the equal sign (<%%>) to simply execute ruby without outputting
Related
sorry but i'm starting with Ruby on rails.the solution will surely seem simple.
i have a food/index view with this line
<%= #foods.each do |food| %>
<%= food.title %>
<%= food.description%>
<%= food.price %>
home
<%end%>
foods_controller
def index
#foods = Food.all
end
it works but ,i have a list of food with the home link for each but i have all my array foods params at the bottom ,with id or created at for example.
i would like to hide this.
could you help me,please.
Change
<%= #foods.each do |food| %>
to
<% #foods.each do |food| %>
You just want to start a bit of ruby code in this bit, you don't want to actually 'print' the results to your view yet.
I'm in the process of refactoring some code. I'm trying to use arrays in my view as part of a for loop that makes columns in a table.
I have defined the arrays in my controller:
subjects_controller.rb
def index
...
#CRFS_TO_VIEW = [Baseline, TreatmentCompletion]
#CRF_PATH = {Baseline => 'baseline_path', TreatmentCompletion => tc_path}
end
So my goal; as the function iterates over #CRFS_TO_VIEW, the correct path is selected from #CRF_PATH and appended to the link_to function.
indext.html.erb
<% #CRFS_TO_VIEW.each do |crf| %>
<% path = #CRF_PATH[crf] %>
<%= link_to "edit", path(crf.where(subject_id: sub.subject_id).first %>
<% end %>
I also tried :
<%= link_to "edit", #CRF_PATH[crf](crf.where(subject_id: sub.subject_id).first %>
Which didn't work. I feel I must be getting close, any help or insight would be greatly appreciated.
Thanks.
A few things:
a. You should save yourself some time and loop through the dictionary instead of the array:
<% #CRF_PATH.each do |crf, path| %>
...
<% end %>
b. You are getting a string from the loop - you can invoke the equivalent method with send:
<%= send(path, ...) %>
c. You can simplify your retrieval of the objects using:
crf.find_by(subject_id: sub.subject_id)
That said - this seems like a pretty bad way of doing things. I'd recommend instead adding a view helper:
def crf_path(crf)
case crf
when Baseline then baseline_path(crf)
...
end
With something like this you could use (notice changed the find_by to find_by! for safety as well):
<% #CRFS_TO_VIEW.each do |crf| %>
<%= link_to "edit", crf_path(crf.find_by!(subject_id: sub.subject_id) %>
<% end %>
Finally instance variables should NOT be named upper case. If you want to use a constant define it as a constant (otherwise use lower case names).
Is there a Ruby (preferably) or Rails way to check if the second index of an array exists?
In my Rails (4.2.6) app I have the following code in my view that shows the first two thumbnails for an array of photos:
<% if array.photos.any? %>
<%= image_tag array.photos.first.image.url(:thumb) %>
<%= image_tag array.photos[1].image.url(:thumb) %>
<% end %>
However if there is no second item in the array, then there is an error
I've tried the following if statements to make the rendering of the second thumbnail conditional, but they don't work:
<% if array.photos.include?(1) %>
<% if array.photos.second? %>
<% if array.photos[1]? %>
<% if array.photos[1].any? %>
I figured that another way to get what I want would be to simply check the length of the array
Still I was wondering if Ruby (or Rails) had a method or way to check if a specific index in an array exists or not. Thanks in advance
EDIT: To clarify I just want to show the first two thumbnails in the array, if any
You can use an .each, but if you want to follow this approach.
Instead of this:
<%= image_tag array.photos[1].image.url(:thumb) %>
Maybe you can use this:
<%= if(!array.photos[1].nil?) image_tag array.photos[1].image.url(:thumb) %>
Or:
<%= image_tag array.photos[1].image.url(:thumb) unless array.photos[1].nil? %>
Here, why not
(0...array.photos.size).each do |photo|
......
end
array.photos.each do |photo|
......
end
I have a segment of code:
<% #public_address.each do |key| %>
<%= key["address"]["address"] %>
<% end %>
This displays the keys properly, but this code
<% #public_address.each do |key| %>
<% puts key["address"]["address"] %>
<% end %>
displays nothing. What gives? What's the difference between the two?
The <% %> and <%= %> are used in erb to execute ruby code when rendering a template.
Erb is the default template engine in rails.
Difference between <% %> and <%= %>
<% %> Will evaluate the ruby code it contains, but "silently".
Meaning that no output is going to be printed on the rendered page.
<%= %> on the other end, evaluates the ruby it contains and
renders the result on the rendered page.
What's the difference between <% code %> and <%= code %> in Rails erb?
What's puts?
Puts is simply a method from Ruby that is used to print a string at runtime. It has nothing to do with erb templates.
In your first bit of code <%= key["address"]["address"] %>, the <%= %> is rails syntax for evaluating the code inside and returning the value.
In your second bit of code <% puts key["address"]["address"] %>, you use <% %>, which doesn't return an evaluated rails statement. Furthermore, puts is a method that outputs whatever follows it to the stout object. In a command line program, that means printing out to the terminal screen, but in a web app you aren't working with a terminal screen. You are working with controllers and view templates, so it is necessary to use the evaluative <%= %> if you want to return values that will be displayed in the view.
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) %>