Conditionals in Templates

[Russ Abbott]

I'm generating a table. I want the cells to be different depending on the type of the content. How do I test for the type of the content? I'd like to do something like this.

            <tbody>

            {% for row in rows %}

                <tr>

                    {% for cell in row %}

                        <td>

                                {% if isinstance( {{ cell }}, list) %}

                                    <ul>

                                    {% for element in cell %}

                                        <li>{{  element  }}</li>

                                    {% endfor %}

                                    <ul>

                                {% else %}

                                    {{ cell }}

                                {% endif %}

                        </td>

                    {% endfor %}

                </tr>

            {% endfor %}

            </tbody>

But "{% if isinstance( {{ cell }}, list) %}" is not allowed. Apparently I can't call a function in an {% if ...  %} tag.  Is there another way to do this?

Thanks.

[Russ Abbott]

Here's a workaround I came up with.

I defined a class:

class TableValue:

    def __init__(self, value):

        self.value = value

        self.is_list = isinstance(value, list)

Then in the Template I wrote

            <tbody>

            {% for row in rows %}

                <tr>

                    {% for cell in row %}

                        <td>

                                {% if cell.is_list %}

                                    <ul>

                                    {% for element in cell.value %}

                                        <li>{{ element }}</li>

                                    {% endfor %}

                                    </ul>

                                {% else %}

                                    {{ cell.value }}

                                {% endif %}

                        </td>

                    {% endfor %}

                </tr>

            {% endfor %}

            </tbody>

Is that considered decent Django?

On Tuesday, July 3, 2012 12:50:15 PM UTC-7, Russ Abbott wrote:

I'm generating a table. I want the cells to be different depending on the type of the content. How do I test for the type of the content? I'd like to do something like this.

            <tbody>

            {% for row in rows %}

                <tr>

                    {% for cell in row %}

                        <td>

                                {% if isinstance( {{ cell }}, list) %}

                                    <ul>

                                    {% for element in cell %}

                                        <li>{{  element  }}</li>

                                    {% endfor %}

                                    </ul>

                                {% else %}

                                    {{ cell }}

                                {% endif %}

                        </td>

                    {% endfor %}

                </tr>

            {% endfor %}

            </tbody>

[Bill Freeman]

The obvious ways are:

1. Provide a model method that returns a string representing the type
of the instance, compare against that
2. Decorate the instance with an attribute giving the name of the type
as a string...

Can't change the instance (I really think you can still decorate it in
the view, python is flexible that way, but), instead of rows of
instances, return rows of wrapper objects that have the type name as
above, and the original instance as another attribute.

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[Javier Guerra Giraldez]

On Tue, Jul 3, 2012 at 3:39 PM, Bill Freeman <ke1...@gmail.com> wrote:
> The obvious ways are:
>
> 1. Provide a model method that returns a string representing the type
> of the instance, compare against that
> 2. Decorate the instance with an attribute giving the name of the type
> as a string...

3. write a template tag


--
Javier

[Melvyn Sopacua]

4. Don't use polymorphic variables in templates. Handle it in the view
by providing differently named variables (x and x_list for example).


--
Melvyn Sopacua