Problem with IF conditional not working

Question

I have 2 sections, events and activities, that share many fields. But activities doesn't have an eventLevel field as there isn't a level. eventLevel is a radio fieldtype. So I want to insert the eventLevel when it exists and if it doesn't just insert the text "Activity". I've tried various tests on if eventLevel is defined, is null, and length. If there is an eventLevel it displays, but if it's an activity I end up with an empty cell.

{% set events = craft.entries.find({section:'events,activities', eventDate : ">= " ~ now.w3cDate() , order:'eventDate'}) %}
{% if events %}
    {% for entry in events %}
    <tr>
        <td class="col-date">{{ entry.eventDate.format('D j M') }}</td>
        <td><a href="{{ entry.url }}" title="More info about {{ entry.eventName }}">{{ entry.eventName }}</a></td>
        <td>{{ entry.nearestTown }}</td>
        <td>{% if entry.eventLevel is defined %}{{ entry.eventLevel }}{% else %}Activity{% endif %}</td>
    </tr>
    {% endfor %}
{% endif %}

I've also tried the twig default filter with the same result:

{{ entry.eventLevel|default('Activity') }}

Answer 1

To test if a field exists, you'll have to use brackets notation, i.e.

{% if entry['eventLevel'] is defined %}
   ...
{% endif %}

When the field exists, but there isn't a selected option, the Radio FieldType returns an empty string, so you also need to test for entry.eventLevel != ''.

Putting it together, I believe a ternary conditional would perhaps be the most succinct solution in your particular case:

<td>{{ entry['eventLevel'] is defined and entry.eventLevel != '' ? entry.eventLevel : 'Activity' }}</td>

What the above does is to first check if the entry has a property 'eventLevel' – the brackets notation is needed here, to avoid Twig throwing an exception if the entry variable doesn't have the property – before checking if the attribute's value is not an empty string. If both of those statements evaluate to true, then the attribute's value is printed; if not, the string Activity outputs.

This is a bit beside the point, but if you're wondering about the syntax here, the so called ternary operator (e.g. {{ variable ? 'yes' : 'no' }}) is just a kind of a short-hand way to write conditionals. Ternary operators are supported in many programming languages (including JavaScript and PHP).

If you wanted to, you could write out the full conditional and it would work exactly the same:

<td>
    {% if entry['eventLevel'] is defined and entry.eventLevel != '' %}
       {{ entry.eventLevel }}
    {% else %}
       Activity
    {% endif %}
</td>

I'd argue that a ternary operator is more readable, shorter and also makes it easier to deal with potential whitespace issues etc. when inlined in markup like this, though.

Answer 2

How about a conditional to check the entry.type rather than the field? Perhaps more appropriate in this case rather than checking if the field is defined. Something like this:

{% if entry.type.handle == 'events' %}
    {{ entry.eventLevel }}
{% else %}
    Activity
{% endif %}

Alternatively, check the section rather than the entry type with entry.section.handle instead of entry.type.handle.

Answer 3

Is there a chance you once had this field added to both sections? Because this all looks like there's data still left set and you're only expecting "eventLevel" fields to be empty / null for your "activities" section entries, but in fact they are not.

See this SE for why this can happen:
Entries retain field data that has been removed from entry type layout

To solve the problem you could now clear the data, by (a) recreating the radio field with the same settings but with a different handle / name, go through your entries to copy the values, then delete the old field and give the new one the handle and name of the old one. Or you could (b) directly edit the values in the database, the problem with this approach is, you can't sort the records by section.

This would also mean alot of work and I think it's actually not worth it at all, because there's a better way to distinguish whether to show the field's value or not: just check for the entry's section!

Here's how I would do it:

{% set isEvent = entry.section.handle == 'events' %}
{% set isActivity = entry.section.handle == 'activities' %}

{{ isEvent ? entry.eventLevel : 'Activity' }}

You just evaluate entry.section.handle == 'events' and store the result as a variable at the top of your template code. The variable is now available troughout the template and it is now very easy to use this info. You currently only need it once in your code, but this probably changes as you progress with the project.