Is django can modify variable value in template?

This can be done with a Django custom filter

django custom filter

def update_variable(value):
    data = value
    return data

register.filter('update_variable', update_variable)

{% with "true" as data %}
    {% if data == "true" %}
        //do somethings
        {{update_variable|value_that_you_want}}
    {% else %}
        //do somethings
    {% endif %}
{% endwith %}