Question

I am writing a Django view which takes an attached csv file and reads it into the db:

views.py:

def climate_upload(request):
    ...
    if form.is_valid(): # All validation rules pass
        file = request.FILES['attach']

        for line in file:
            line = line.split(';')                 
            report = Site1()
            ...
            # These fields values be empty, integer or float 
            report.mean_air_temp = float(line[4])
            report.min_air_temp = float(line[5])
            report.max_air_temp = float(line[6])
            report.sea_temp = float(line[7])
            report.mean_rel_hum = float(line[8])
            report.precipitation = float(line[9])
            report.save()
        file.close() 

I understand that this is pretty crude code, but if I run this and one of the fields is empty (”) I get a ValueError could not convert string to float:.

I can do this for each field:

            try:
                report.mean_air_temp = float(line[4])
            except(ValueError):
                report.mean_air_temp = None

Which gives me the required results, but does not seem so robust/ elegant.

I would appreciate any guidance as to how to handle this code block.

Answer 1

Wrap the conversion to float in a function call.

def convert_value(val, conversion=float):
    try:
        return conversion(val)
    except ValueError:
        return None

or

report.something = float(line[x]) if line[x] is not None else None