Nrthugu

I have a list of dates:

dates = ['2018-11-13 ', '2018-11-14 ']

and I have a list of weather data for various cities:

weather_data = [('Carbondale', 1875.341, '2018-11-13 '), ('Carbondale', 1286.16, '2018-11-14 '), ('Davenport', 708.5, '2018-11-13 '), ('Davenport', 506.1, '2018-11-14 ')]

i[1] in weather_data is a climate score, based on climatic info for each day. I have shortened the above lists for the sake of this example.

My goal is to find the city with the lowest climate score for each day. I thought a good way to do that would be to put them in a dictionary.

An example of what I want is...

conditions_dict = {'2018-11-13': ('Carbondale',1875.341), ('Davenport', 708.5)}

and my end output would be...

The best weather on 2018-11-13 is in Davenport with a value of 708.5

Basically, if I had a dict with a date as the key, and (city,value) as the value, I could then easily find the lowest value by city for each day.

However, I cannot figure how to make my dictionary look like this. The part I am really struggling with is how to match the date to multiple readings for various cities on one day.

Is using a dictionary even a good way to do this?

You don't really need an intermediate dict with all cities and scores for each date if your goal is find the minimum score and city of each date since you can simply iterate through weather_data and keep track of the lowest score so far and its associated city for each date in a dict:

min_score_of_date = {}

for city, score, date in weather_data:

    if date not in min_score_of_date or score < min_score_of_date.get(date)[1]:

        min_score_of_date[date] = (city, score)

Given your sample input, min_score_of_date would become:

{'2018-11-13 ': ('Davenport', 708.5), '2018-11-14 ': ('Davenport', 506.1)}

This is another way you can go about it if the lowest temperature dates haven't already been filtered for you.

# each date has a tuple of cities and their temperature

conditions = {

    '2018-11-13': (

        ('Carbondale',1875.341),

        ('Davenport', 708.5)

    )

}



# loop through every date

for date, cities in conditions.items():

    # for every date, loop through its values

    # grab its temperateure and add to the list

    # them find the minimun temperature



    # get all tempertures

    tempertures = [_[1] for _ in cities]

    # get minimum temperature

    min_temperture = min(tempertures)



    # loop throught all cities

    for city in cities:

        # if a city matches min_temperature do whats bellow

        if min_temperture in city:

            # city name

            name = city[0]

            # city temperture

            temperture = str(city[1])



            print(

                "The best weather on "

                + date

                + "is in "

                + name + " with a value of "

                + temperture

            )