Dynamically populate the Flask WTForms Select field from a csv file?

Question

I am using Flask, Pandas, WTForms.

I want to populate a selectfield with data from a csv file.

I have

routes.py 
forms.py
tabular.html

I create form in forms.py then via routes.py display it into tabular.html.

Forms.py

class QueryTableForm(FlaskForm):
    state_select = []
    district_select = []

    country = SelectField(u'Country', choices=state_select)
    state = SelectField(u'State', choices=district_select)
    submit = SubmitField(u'Search')

Routes.py

#csv imports

country_wise_data = list(pd.read_csv('country_data.csv').values)
state_wise_data = list(pd.read_csv('state_data.csv').values)
district_wise_data = list(pd.read_csv('district_data.csv').values)

@app.route("/tabular", methods=['GET', 'POST'])
@login_required
def tabular():
    form = QueryTableForm()
    if form.validate_on_submit():
        post = Post(title=form.country.data, content=form.state.data)
        flash('Your Selection is Registered!', 'success')
    return render_template('tabular.html', state_wise_data = state_wise_data,
                           country_wise_data=country_wise_data, district_wise_data=district_wise_data, 
                           title='Tabular Data', form=form, legend='Tabular',
                           max=17000, date=date)

tabular.html

<form method="POST" action="">
...
{{ form.country.label }} {{ form.country }}
{{ form.state.label }} {{ form.state}}
...
        </form>

csv file format

State,Confirmed,Recovered,Deaths,Active,Last_Updated_Time,,,,,,
USA,3458996,2834473,58245,564746,12-04-2021 22.57,,,,,,
India,1180398,1123133,4815,52128,13-04-2021 19.02,,,,,,

Now I want to pull only the values "USA","India" etc and populate in the selectfield "form.country". I have tried to do a for loop on routes.py. But how do I pass it on to the HTML file ? I also tried to do a for loop via Jinja on the HTML file.

How do I dynamically populate the "choices" attribute of the WTF selectfield from the html file ?

Andrew Clark Andrew Clark · Accepted Answer · 2021-04-20T14:33:55

@app.route("/tabular", methods=['GET', 'POST'])
@login_required
def tabular():
    form = QueryTableForm()
    form.country.choices = country_wise_data
    if form.validate_on_submit():
        post = Post(title=form.country.data, content=form.state.data)
        flash('Your Selection is Registered!', 'success')
    return render_template('tabular.html', state_wise_data = state_wise_data,
                           country_wise_data=country_wise_data, district_wise_data=district_wise_data, 
                           title='Tabular Data', form=form, legend='Tabular',
                           max=17000, date=date)

Dynamically populate the Flask WTForms Select field from a csv file?

1 Answers