if with jinja2 always false [duplicate]

Question

I have the following code, I get persons from sqlalchemy query and Flask, I want to print the shift only when is different, but the condition is always false. I don't know what happen:

                           {% set actual_shift = 0 %}
                           {% for person in persons %}
                              {% if actual_shift == person.shift|safe %}
                                  <p></p>
                              {% else %}
                                  {% set actual_shift = person.shift |safe %}
                                  {% set actual_shift = actual_shift |int %}
                                  <p>{{ actual_shift }}</p>
                              {% endif %}
                              <label class="form-check-label" for="{{ person.username }}"><input type="checkbox" value="{{person.person_id}}" class="form-check-input" id="{{ person.username }}" name="persons" checked>{{person.fname}} {{person.lname}}</label>
                           {% endfor %}

Answer 1

If you want to assign a new value to your variable inside a loop of jinja2, you should define a namespace. You can find the documentation for this here.

{% set actual = namespace(shift=0)  %}
{% for person in persons %}
  {% if actual.shift == person.shift %}
      <p></p>
  {% else %}
      {% set actual.shift = person.shift %}
      <p>{{ actual.shift }}</p>
  {% endif %}
{% endfor %}