Iterating multiple for loops based on the same list

Question

In my django template, I need to add two loops based on the same zipped list. Unfortunately, only the first loop seems to be executed.

I have the following code in views.py:

@login_required
def edit_doctorslots(request, cliniclabel, doctor_id):
    doctor_id=int(doctor_id)
    doc = get_object_or_404(doctor, docid=doctor_id)
    cl = Clinic.objects.get(label=cliniclabel)
    print("Clinic name", cl.name)
    formslot = SlotForm()
    formspecialdays = SpecialdaysForm()
    formweekdays = WeekdaysForm()
    weekdays = ['Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday']
    weekdaynum = [0,1,2,3,4,5,6]
    weekzip = zip(weekdays, weekdaynum)
    newweekzip = weekzip
    return render(request, 'clinic/editslots.html', {'rnd_num': randomnumber(), 'clinic': cl, 'doctor': doc, 'formslot': formslot, 'formspecialdays': formspecialdays, 'formweekdays': formweekdays, 'weekzip': weekzip, 'newweekzip': newweekzip })

My template:

<div class="container ml-5 mr-5">
    <div class="jumbotron slotgroup slotavailable mb-1 mt-5" id="jumbo_week_avail">
      <div class="slot-header" role="alert">
        Enter your weekly consultation hours at {{ clinic.name }}. This will supercede regular hours. If you specify some week days, but not others, you will be assumed to be on leave during those days. If you dont specify any week days, but specify regular hours, you will be assumed to be working on all days.
      </div>
      {% for weekday, weeknum in weekzip %}
      <div class="row row_week_avail" id="row_week_avail{{ weeknum }}">
        <div class="col-md-1 mr-2">
          <label class="switch switch_type1 greenswitch" role="switch">
          <input type="checkbox" id="chk_week_avail{{ weeknum }}" class="switch__toggle">
          <span class="switch__label"></span>
        </label>
        </div>
        <div class="col-md-2 text-right">
          <span class="">{{ weekday }}</span>
        </div>
          <div class="col-md-6">
            <input type="text" class="form-control timeinput" id="start_week_avail{{ weeknum }}" aria-describedby="mainslotstarthelp" placeholder="Starts at">
            <small id="mainslotstarthelp" class="form-text text-muted">Start time of consultations</small>
          </div>
          <div class="col-md-6">
            <input type="text" class="form-control timeinput" id="end_week_avail{{ weeknum }}" aria-describedby="mainslotendhelp" placeholder="Ends at">
            <small id="mainslotendhelp" class="form-text text-muted">End time of consultations</small>
          </div>
          <div class="col-md-6">
              <a class="btn btn-primary AddHoursBtn" id="btn_week_avail{{ weeknum }}"><i class="fas fa-plus"></i></a>
          </div>
      </div>
      {% endfor %}
    </div>

    <div class="jumbotron slotgroup slotunavailable mb-1" id="jumbo_week_break">
      <div class="slot-header" role="alert">
        Break Time (Unavailable Hours) <span class="text-muted">Time in between regular period, where you are unavailable.</span>
      </div>
      {% for weekday, weeknum in weekzip %}
        <div class="row row_week_break" id="row_week_break{{ weeknum }}">
          <div class="col-md-1 mr-2">
            <label class="switch switch_type1 greenswitch" role="switch">
            <input type="checkbox" id="chk_week_break{{ weeknum }}" class="switch__toggle">
            <span class="switch__label"></span>
          </label>
          </div>
          <div class="col-md-2 text-right">
            <span class="">{{ weekday }}</span>
          </div>
            <div class="col-md-6">
              <input type="text" class="form-control timeinput" id="start_week_break{{ weeknum }}" aria-describedby="mainslotstarthelp" placeholder="Starts at">
              <small id="mainslotstarthelp" class="form-text text-muted">Start time of consultations</small>
            </div>
            <div class="col-md-6">
              <input type="text" class="form-control timeinput" id="end_week_break{{ weeknum }}" aria-describedby="mainslotendhelp" placeholder="Ends at">
              <small id="mainslotendhelp" class="form-text text-muted">End time of consultations</small>
            </div>
            <div class="col-md-6">
                <a class="btn btn-primary AddHoursBtn" id="btn_week_break{{ weeknum }}"><i class="fas fa-plus"></i></a>
            </div>
        </div>
      {% endfor %}
    </div>
</div>

While rendering, the second for loop does not iterate. Rendered html:

<div class="container ml-5 mr-5">
    <div class="jumbotron slotgroup slotavailable mb-1 mt-5" id="jumbo_week_avail">
      <div class="slot-header" role="alert">
        Enter your weekly consultation hours at Dr Joel's ENT Clinic. This will supercede regular hours. If you specify some week days, but not others, you will be assumed to be on leave during those days. If you dont specify any week days, but specify regular hours, you will be assumed to be working on all days.
      </div>

      <div class="row row_week_avail" id="row_week_avail0">
        <div class="col-md-1 mr-2">
          <label class="switch switch_type1 greenswitch" role="switch">
          <input type="checkbox" id="chk_week_avail0" class="switch__toggle">
          <span class="switch__label"></span>
        </label>
        </div>
        <div class="col-md-2 text-right">
          <span class="">Sunday</span>
        </div>
          <div class="col-md-6">
            <input type="text" class="form-control timeinput" id="start_week_avail0" aria-describedby="mainslotstarthelp" placeholder="Starts at">
            <small id="mainslotstarthelp" class="form-text text-muted">Start time of consultations</small>
          </div>
          <div class="col-md-6">
            <input type="text" class="form-control timeinput" id="end_week_avail0" aria-describedby="mainslotendhelp" placeholder="Ends at">
            <small id="mainslotendhelp" class="form-text text-muted">End time of consultations</small>
          </div>
          <div class="col-md-6">
              <a class="btn btn-primary AddHoursBtn" id="btn_week_avail0"><i class="fas fa-plus"></i></a>
          </div>
      </div>

      <div class="row row_week_avail" id="row_week_avail1">
        <div class="col-md-1 mr-2">
          <label class="switch switch_type1 greenswitch" role="switch">
          <input type="checkbox" id="chk_week_avail1" class="switch__toggle">
          <span class="switch__label"></span>
        </label>
        </div>
        <div class="col-md-2 text-right">
          <span class="">Monday</span>
        </div>
          <div class="col-md-6">
            <input type="text" class="form-control timeinput" id="start_week_avail1" aria-describedby="mainslotstarthelp" placeholder="Starts at">
            <small id="mainslotstarthelp" class="form-text text-muted">Start time of consultations</small>
          </div>
          <div class="col-md-6">
            <input type="text" class="form-control timeinput" id="end_week_avail1" aria-describedby="mainslotendhelp" placeholder="Ends at">
            <small id="mainslotendhelp" class="form-text text-muted">End time of consultations</small>
          </div>
          <div class="col-md-6">
              <a class="btn btn-primary AddHoursBtn" id="btn_week_avail1"><i class="fas fa-plus"></i></a>
          </div>
      </div>

      <div class="row row_week_avail" id="row_week_avail2">
        <div class="col-md-1 mr-2">
          <label class="switch switch_type1 greenswitch" role="switch">
          <input type="checkbox" id="chk_week_avail2" class="switch__toggle">
          <span class="switch__label"></span>
        </label>
        </div>
        <div class="col-md-2 text-right">
          <span class="">Tuesday</span>
        </div>
          <div class="col-md-6">
            <input type="text" class="form-control timeinput" id="start_week_avail2" aria-describedby="mainslotstarthelp" placeholder="Starts at">
            <small id="mainslotstarthelp" class="form-text text-muted">Start time of consultations</small>
          </div>
          <div class="col-md-6">
            <input type="text" class="form-control timeinput" id="end_week_avail2" aria-describedby="mainslotendhelp" placeholder="Ends at">
            <small id="mainslotendhelp" class="form-text text-muted">End time of consultations</small>
          </div>
          <div class="col-md-6">
              <a class="btn btn-primary AddHoursBtn" id="btn_week_avail2"><i class="fas fa-plus"></i></a>
          </div>
      </div>

      <div class="row row_week_avail" id="row_week_avail3">
        <div class="col-md-1 mr-2">
          <label class="switch switch_type1 greenswitch" role="switch">
          <input type="checkbox" id="chk_week_avail3" class="switch__toggle">
          <span class="switch__label"></span>
        </label>
        </div>
        <div class="col-md-2 text-right">
          <span class="">Wednesday</span>
        </div>
          <div class="col-md-6">
            <input type="text" class="form-control timeinput" id="start_week_avail3" aria-describedby="mainslotstarthelp" placeholder="Starts at">
            <small id="mainslotstarthelp" class="form-text text-muted">Start time of consultations</small>
          </div>
          <div class="col-md-6">
            <input type="text" class="form-control timeinput" id="end_week_avail3" aria-describedby="mainslotendhelp" placeholder="Ends at">
            <small id="mainslotendhelp" class="form-text text-muted">End time of consultations</small>
          </div>
          <div class="col-md-6">
              <a class="btn btn-primary AddHoursBtn" id="btn_week_avail3"><i class="fas fa-plus"></i></a>
          </div>
      </div>

      <div class="row row_week_avail" id="row_week_avail4">
        <div class="col-md-1 mr-2">
          <label class="switch switch_type1 greenswitch" role="switch">
          <input type="checkbox" id="chk_week_avail4" class="switch__toggle">
          <span class="switch__label"></span>
        </label>
        </div>
        <div class="col-md-2 text-right">
          <span class="">Thursday</span>
        </div>
          <div class="col-md-6">
            <input type="text" class="form-control timeinput" id="start_week_avail4" aria-describedby="mainslotstarthelp" placeholder="Starts at">
            <small id="mainslotstarthelp" class="form-text text-muted">Start time of consultations</small>
          </div>
          <div class="col-md-6">
            <input type="text" class="form-control timeinput" id="end_week_avail4" aria-describedby="mainslotendhelp" placeholder="Ends at">
            <small id="mainslotendhelp" class="form-text text-muted">End time of consultations</small>
          </div>
          <div class="col-md-6">
              <a class="btn btn-primary AddHoursBtn" id="btn_week_avail4"><i class="fas fa-plus"></i></a>
          </div>
      </div>

      <div class="row row_week_avail" id="row_week_avail5">
        <div class="col-md-1 mr-2">
          <label class="switch switch_type1 greenswitch" role="switch">
          <input type="checkbox" id="chk_week_avail5" class="switch__toggle">
          <span class="switch__label"></span>
        </label>
        </div>
        <div class="col-md-2 text-right">
          <span class="">Friday</span>
        </div>
          <div class="col-md-6">
            <input type="text" class="form-control timeinput" id="start_week_avail5" aria-describedby="mainslotstarthelp" placeholder="Starts at">
            <small id="mainslotstarthelp" class="form-text text-muted">Start time of consultations</small>
          </div>
          <div class="col-md-6">
            <input type="text" class="form-control timeinput" id="end_week_avail5" aria-describedby="mainslotendhelp" placeholder="Ends at">
            <small id="mainslotendhelp" class="form-text text-muted">End time of consultations</small>
          </div>
          <div class="col-md-6">
              <a class="btn btn-primary AddHoursBtn" id="btn_week_avail5"><i class="fas fa-plus"></i></a>
          </div>
      </div>

      <div class="row row_week_avail" id="row_week_avail6">
        <div class="col-md-1 mr-2">
          <label class="switch switch_type1 greenswitch" role="switch">
          <input type="checkbox" id="chk_week_avail6" class="switch__toggle">
          <span class="switch__label"></span>
        </label>
        </div>
        <div class="col-md-2 text-right">
          <span class="">Saturday</span>
        </div>
          <div class="col-md-6">
            <input type="text" class="form-control timeinput" id="start_week_avail6" aria-describedby="mainslotstarthelp" placeholder="Starts at">
            <small id="mainslotstarthelp" class="form-text text-muted">Start time of consultations</small>
          </div>
          <div class="col-md-6">
            <input type="text" class="form-control timeinput" id="end_week_avail6" aria-describedby="mainslotendhelp" placeholder="Ends at">
            <small id="mainslotendhelp" class="form-text text-muted">End time of consultations</small>
          </div>
          <div class="col-md-6">
              <a class="btn btn-primary AddHoursBtn" id="btn_week_avail6"><i class="fas fa-plus"></i></a>
          </div>
      </div>

    </div>

    <div class="jumbotron slotgroup slotunavailable mb-1" id="jumbo_week_break">
      <div class="slot-header" role="alert">
        Break Time (Unavailable Hours) <span class="text-muted">Time in between regular period, where you are unavailable.</span>
      </div>

    </div>
</div>

Why does this happen?

Answer 1

In Python 3, zip returns a generator: once iterated, it is exhausted. You should convert it to a list first:

weekzip = list(zip(weekdays, weekdaynum))