Ruby on Rails: testing if values do exist?

Question

I'm trying to test if my values are existing... Not sure how to do this, I'm just starting to learn Ruby on Rails. Hopefully someone can point me to the right direction?

Lets say I have this block of codes:

@lv = {'apple' => ['red', 'round'], 'iPhone' => ['device', 'phone']}

if params[:var]
    @lv.each do |key, tags|
        if params[:var] == key
            lvtags = @lv[params[key]]
            lvtags.each do |tag|
                @tags = client.tag_recent_media(tag)
            end
        end
    end
end

I'm trying to see if the loop through the if params[:var] == key works. I'd like to somehow output like an alert() type thing, to test if key has a value? Is there something like alert(key)? where it'll show if key has something? Or if I can test if lvtags has a value that its supposed to pop out?

For instance, if ?var=0

Then I'd like to test alert(lvtags), and thus this is supposed to pop out apple or something, some value associated to lvtags = @lv[params[key]]. How do we normally test something like this in rails?

Thanks

tessi · Accepted Answer · 2013-04-14 23:30:10Z

1

You can do a puts key. Puts converts its first param to string and outputs it in the stdout (your console).

It might be easier for you to use a debugger, though. You can open a console debugger (think gdb) with

require 'debugger'; debugger

Be sure to install the debugger gem first. Put the following in your Gemfile

gem 'debugger', group: [:development, :test]

Edit: added a link to the debugger gem's github page.

edited Apr 14, 2013 at 23:30

answered Apr 14, 2013 at 23:22

tessi

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4 Comments

hellomello Over a year ago

I'm trying to implement puts in my views, but its not even printing out a test I'm doing: <%= puts "test" %>, I even tried <%= print "test" %>, no working?

tessi Over a year ago

I expected the puts to be within your controller (within @lv.each do). However puts in general should work in your view too. But it does not display any information in your view. It displays it in your console (where you typed rails server).

Simon Perepelitsa Over a year ago

It is better to use p than puts for debugging since it will print more useful info (e. g. nil instead of nothing)

fotanus Over a year ago

You should really give some effort and learn how to use the debugger. I'm not sure why ruby community don't always use it - it is way better than a puts or p command. After you print something, now that you know the result, you might want to know what is in other variable. Since debugger stops the flow, you can just look in the other variable without a new request and code edit. Time saver.

Arnelle Balane · Accepted Answer · 2013-04-14 23:26:14Z

0

You can just log it in your console.

Rails.logger.info key.inspect # or whichever's value you want to check

It's also helpful when checking objects

answered Apr 14, 2013 at 23:26

Arnelle Balane

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2 Comments

hellomello Over a year ago

Sorry for this newbie question, but can you explain where I would put this? I have the loop in my controller. Not sure where I should apply the code you provided?

Arnelle Balane Over a year ago

if you want to check the key in every iteration of the loop, you can place it inside the @lv.each do |key, tags| loop

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