[Tutor] Writing for loop output to csv

[Peter Otten]

Cameron Simpson wrote:

> On 06Sep2018 12:32, Brandon Creech <bdcreech91 at gmail.com> wrote:
>>Hi, I am working to forecast the temperatures for the next 5 days using an
>>API and a for loop. I would like write the output of this loop to a csv in
>>this format::
>>
>>Columns: City, min1, max1, min2, max2,min3,max3,min4,max4,min5,max5
>>data:         Athens,Greece 25.4,26.7....etc.
>>                 Nantou,Taiwan 16.18, ......etc

> print call for the output.  The csv module provides a writer object which
> does all the heavy lifting for you: turns strings into quotes strings,
> puts in commas, etc. Try this change:
> 
>   csvw = csv.writer(sys.stdout)
>   for city, coords in cities.items():
>       weather = ForecastIO.ForecastIO( api_key, latitude=coords[0],
>       longitude=coords[1] ) 
>       daily = FIODaily.FIODaily(weather)
>       for day in range(2,7):
>           day_data = daily.get_day(day)
>           csvw.writerow([city, day_data['temperatureMax'],
>           day_data['temperatureMin']])

If you want all min/max pairs in the same row you can prebuild that row in a 
list. With minimal changes to Cameron's code:

# untested
csvw = csv.writer(sys.stdout)
for city, coords in cities.items():
    weather = ForecastIO.ForecastIO(
        api_key, latitude=coords[0], longitude=coords[1]
    )
    daily = FIODaily.FIODaily(weather)
    row = [city]
    for day in range(2, 7):
        day_data = daily.get_day(day)
        row.append(day_data['temperatureMin'])
        row.append(day_data['temperatureMax'])
    csvw.writerow(row)