Use list to set label name in WTForms fieldlist

Question

I want to use a FieldList to build a form via WTForms. I have a list of strings such as: vehicles = ['car', 'truck', 'van']

I have constructed my form so that I have: vehicles = ['car', 'truck', 'van']

class VehicleForm(Form):
    value = DecimalField()

class VehicleEntryForm(FlaskForm):
    values = FieldList(
        FormField(VehicleForm),
        min_entries=len(vehicles))
    submit = SubmitField('Submit')

I am rending using jinja as:

<form action="" method="post">
    {{ form.hidden_tag() }}
    {% for value in form.values %}
        {{value.label}}{{value()}}
    {% endfor %}
        {{ form.submit() }}
</form>

This creates a form with generic labels as one would expect. The html for the form label comes out as:

...<label for="values-0-value">Value</label>...
...<label for="values-1-value">Value</label>...
...<label for="values-2-value">Value</label>...

The question is how can I update the label value on the backend using my list. I tried:

form = VehicleEntryForm()
ii = 0
for field in form.values:
    field.label = labels[ii]
    ii+=1

and then updated html/jinja to:

<form action="" method="post">
    {{ form.hidden_tag() }}
    {% for value in form.values %}
        {{value.label}}{{value()}}
    {% endfor %}
        {{ form.submit() }}
</form>

However, this resulted in now having:

car<table id="values-0" label="car"><tr><th><label for="values-0-value">Value</label></th><td><input id="values-0-value" name="values-0-value" required type="text" value=""></td></tr></table>

truck<table id="values-1" label="truck"><tr><th><label for="values-1-value">Value</label></th><td><input id="values-1-value" name="values-1-value" required type="text" value=""></td></tr></table>

This gets me halfway there... but how do I get replace of the <label for="values-0-value">Value</label> with <label for="values-0-value">Car</label> ?

Note: the vehicles list comes from a model query, so can be variable in length... which is why I tried this (if it was always just same 3 things, I'd just type it in).

I am open to alternative approaches if FieldList and FormField are not the way to do it.

Answer 1

Using FieldList, new fields can be added using append_entry()

This function doesn't give an option to add a label, but it can be edited after being added in form.values.entries .

vehicles = ['car', 'truck', 'van']
form = VehicleEntryForm()
for vehicle in vehicles:
    form.values.append_entry(data='foo')
    form.values.entries[-1].label.text = vehicle