In Jinja2, how do you test if a variable is undefined?
{% if variable is defined %}
is true if the variable is None
.
Since not is None
is not allowed, that means that
{% if variable != None %}
is really your only option.
From the Jinja2 template designer documentation:
{% if variable is defined %}
value of variable: {{ variable }}
{% else %}
variable is not defined
{% endif %}
You could also define a variable in a jinja2 template like this:
{% if step is not defined %}
{% set step = 1 %}
{% endif %}
And then You can use it like this:
{% if step == 1 %}
<div class="col-xs-3 bs-wizard-step active">
{% elif step > 1 %}
<div class="col-xs-3 bs-wizard-step complete">
{% else %}
<div class="col-xs-3 bs-wizard-step disabled">
{% endif %}
Otherwise (if You wouldn't use {% set step = 1 %}
) the upper code would throw:
UndefinedError: 'step' is undefined