CODEWITHSUNDEEP
ruby-on-railsrubyruby-on-rails-4
neanderslob
neanderslob

Reputation: 2693

Unexpected trouble comparing numbers

I'm writing a helper method that adds a class to an element depending on whether two numbers are equal to eachother. My code is as follows:

<% for note in @company.convertible_notes.each %>
    <% if note.id %>
        <li class="tab <%= note_nav(params, note.id) %>"><%= link_to "#{note.security_series} #{note.security_class} Note", convertible_note_convertible_notees_path(note) %></li>
    <% end %>
<% end %>

note_nav calls the following helper:

def note_nav(params, note)
    "active" if params[:controller]=="convertible_notees" && note.to_s==params[:converible_note_id].to_s
end

Now the surprising thing is that I cannot get the expression note.to_s==params[:converible_note_id].to_s to register true. Even when I know the two numbers being compared are both "1". I checked it using my log: 

logger.debug "are they equal? #{note.to_s==params[:converible_note_id].to_s} note.id is #{note} note params are #{params[:convertible_note_id]}"

Which yields the following log entry:

are they equal? false note.id is 1 note params are 1

I would guess that they're two different types but given that I've converted both of them to_s, I don't know how that would be an issue. I've used this exact same technique on a few combinations of other models and have been completely error free. Any idea as to what might be going on?

Thanks in advance

Upvotes: 1

Views: 52

Answers (2)

7stud
7stud

Reputation: 48599

You could also get that output if one of the variables contains non-printing characters:

note = "1\000"

params = {
  convertible_note_id: 1
}

puts "are they equal? #{note.to_s==params[:convertible_note_id].to_s}"
puts "note.id is #{note} note params are #{params[:convertible_note_id]}"

--output:--
are they equal? false
note.id is 1 note params are 1

To see what's really in a string, you should always use inspect():

p note.to_s, params[:convertible_note_id].to_s

--output:--
"1\u0000"
"1"

Upvotes: 0

peter
peter

Reputation: 42182

Look at your test

"are they equal? #{note.to_s==params[:converible_note_id].to_s} note.id is #{note} note params are #{params[:convertible_note_id].to_s}"

:converible_note_id and :convertible_note_id are other keys, a type error

Upvotes: 2

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