My website is printing out elements such as (SnO), however, it should be printing SnO, but it is adding a weird space and it is printing like Sn O. It is adding a space between the element for no reason. My code is on the listed below.
<% saved_element = ""%>
<% sensor.base_material.elests.each_with_index do |elest, v| %>
<% if elest.element.include? "O" %>
<% saved_element = elest %>
<% else %>
<%=elest.element.split('-').last %>
<% if elest.stoich != 1 %>
<sub><%=elest.stoich.to_i%></sub>
<% end %>
<% end %>
<% if v == sensor.base_material.elests.length-1 %>
<%=saved_element.element.split('-').last%>
<% if saved_element.stoich != 1 %>
<sub><%=saved_element.stoich.to_i %></sub>
<% end %>
<% end %>
<% end %>
The code you show is full of white spaces (at the beginning of each line). Those are printed on the HTML and compacted as one space. Also, when you print a value, it adds an space at the end, you can supress that usign <%= ... -%> (note the dash at the end)
https://www.howtobuildsoftware.com/index.php/how-do/Nzr/ruby-on-rails-erb-suppressing-spaces-in-erb-template
Anyway, I would move all that logic to a helper method, that's what helper methods are for.
Related
I have 100 shoes with shoe names. I don't want to display all 100 in a row, I want to display 5, then a green box, then the next 5, and the same green box... but there is something wrong with my code.
<% #shoes.each.with_index(1) do |shoe, index| %>
<% while index < 101 do %>
<%= shoe.name %>
<% if index % 5 == 0 %>
<%= Green Box %>
<% end %>
You're looking for in_groups_of(x)
<% #shoes.in_groups_of(5) do |shoe_groups| %>
<% shoe_groups.each do |shoe| %>
<%= shoe.name %>
<% end %>
<%= 'Green Box' if shoe_groups.size % 5 == 0 %>
<% end %>
Your syntax is wrong in several places - the enumerator is wrong, you are missing several end statements. Also, even though index is not a reserved word, the generally accepted style for an index is a single-letter variable like i. It should be
<% #shoes.each_with_index(1) do |shoe, i| %>
<% while i < 101 do %>
<%= shoe.name %>
<% if i % 5 == 0 %>
<%= Green Box %>
<% end %>
<% end %>
<% end %>
(But personally, I would not do the index < 101 block in the view - I would make sure that the controller that generates #shoes and sends it to the view only sends 100 elements in the array)
Here, I have 10 columns i.e., answer1, answer2, answer3, ..., answer10 in the table MgAnswer.
I have to check whether each column value is present or not. Only if it present,then I have to display it in the page.
Im giving column names dynamically within for loop
<% (1..10).each do |i| %>
<% if MgAnswer."answer#{i}".present? %>
<%= MgAnswer."answer#{i}" %>
<% end %>
<% end %>
Im ending up with Syntax error.
You can indeed dynamically invoke methods in ruby, but this is not the syntax. Instead do
<% (1..10).each do |i| %>
<% if MgAnswer.public_send("answer#{i}").present? %>
<%= MgAnswer.public_send("answer#{i}") %>
<% end %>
<% end %>
It should seem like the following:
<% (1..10).each do |i| %>
<%= MgAnswer.send("answer#{i}") %>
<% end %>
Since ruby can't evaluate line as MgAnswer."method". Also you can just skip if condition, because it will be evaluated to empty string "".
I want to print out a list of links separated by commas in Rails.
Heres what I've got:
<%= topics.each do |topic| %>
<a href="<%= topic.link %>" ><%= topic.name %></a>
,
<% end %>
Heres what I want:
Thing A,
Thing B,
Thing C
But right now I get an extra comma on the last iteration of the loop! What should I do?
One way of doing this is with map then Array#join:
<%= topics.map { |topic| link_to(topic.name, topic.link) }.join(',').html_safe %>
if you want to do minimum possible change to your code, you can use the following
<%= topics.each do |topic| %>
<a href="<%= topic.link %>" ><%= topic.name %></a>
<% if(topic != topics.last) %>
,
<% end %>
<% end %>
How about using each_with_index, and only put comma before the content unless it's not the first item.
<% topics.each_with_index do |topic, i| %>
<% if i > 0 %>
,
<% end %>
<%= topic.name %>
<% end %>
I made it in one line call (for active records collections) using the concat helper:
<% concat (',') if e.bills.last != b %>
concat is an ERB helper (TextHelper) to add some HTML without the <%= %> syntax, helpful to add few characters.
Here is the full code to make it clear:
<% event.bills.each do |b| %>
<%= link_to(b.number.to_s, bill_display_path(b)) %>
<% concat (',') if e.bills.last != b %>
<% end %>
Simply try this. It works for me
<%= topics.map{|p| p.topic.name}.join(",") %>
You can do the following to print out the comma for all items except for the last:
<% topics.each do |topic| %>
<%= topic %>
<%= "," if topic != topics.last %>
<% end %>
This will check if the current item in the loop is the last item, and will use the <%= %> syntax to output the comma.
So I have standart scaffold cycle that prints a string of tags of a meet.
<% #meets.each do |meet| %>
<p class="MeetTags"><%= meet.tags %></p>
<% end %>
How can I separate string of for example 3 words, so that each would be in separate box.
Thank you!
You can do some think like
<% #meets.each do |meet| %>
<% meet_tags = meet.tags.split(' ') %>
<% meet_tags.each do |meet_tag|%>
<p class="MeetTags"><%= meet_tag %></p>
<%end%>
<% end %>
your problem is that meet.tags is an array, so you're telling rails to display the array: that's why you're seeing the square braces.
If you want to split tags into groups of 3, and then show them separated by spaces, you could do this:
<% #meets.each do |meet| %>
<% tag_arr = meet.tags.split(' ') %>
<% tag_arr.in_groups_of_3.each do |tag_subarr|%>
<p class="MeetTags"><%= tag_subarr.reject(&:blank?).join(" ") %></p>
<%end%>
<% end %>
I'm using .reject(&:blank?) because the in_groups_of method will pad the last subarray out with nil, which will mess up your formatting, and maybe cause other problems if you try and do anything with the member elements of tag_subarr.
Assuming that your tags are joined with space:
<% #meets.each do |meet| %>
<% meet.tags.split(' ').each do |word| %>
<p class="MeetTags"><%= word %></p>
<% end %>
<% end %>
I have a a helper that contains a simple on and off switch. I know I have it working because it's working on other pages. However, on this particular page it won't work.. I think its because theres an end within the if else, so it ends the if else early. Here's the code:
I believe this part is working:
<% if popup == "off" %>
<% content_for :main do %>
<% end %>
This part not so much:
<% if popup == "off" %>
<% end %> << this end should be displayed if popup = off
<% end %>
You could do this:
<% if popup == "off" %>
<%= "<% end %>" %> << this end should be displayed if popup = off
<% end %>
or try this:
<% if popup == "off" %>
<% end %> << this end should be displayed if popup = off
<% end %>
If you just want the word end to be displayed, don't enclose it in tags. Anything enclosed in tags is interpreted as Ruby code, anything not is printed exactly as it is.
<% if popup == "off" %>
end << this will now be interpreted as text, not ruby code
<% end %>
ERB (and Ruby) doesn't work like that.
I think you're treating it like you are trying to end an HTML tag instead of an end to a Ruby block, and that you want everything in between those two code segments to run in the content_for block.
Here's what you need. Everything in between will be included in the content_for block:
<% if popup == "off" %>
<% content_for :main do %>
your block code will be evaluated here.
<% end %>
<% end %>
Seems all the suggestions of doing <%= "<% end %>" %> results in a syntax error.. May seem like easy way out by ended up just restructuring my app and got rid of the requirement of <% content_for :main do %>