遍历CSV文件

Question

I have to produce a function that will return a tuple containing the maximum temperature in the country and a list of the cities in which that temperature has been recorded. The data was input as a CSV file in the format:

Month, Jan, Feb, March....etc. 

So far I have managed to get the maximum temperature but when it tries to find the cities in which that temperature was found, it comes up as an empty list.

def hottest_city(csv_filename):
    import csv
    file = open(csv_filename)
    header = next(file)
    data = csv.reader(file)
    city_maxlist = []
    for line in data:
        maxtemp = 0.0
        for temp in line[1:]:
            if float(temp >= maxtemp:
                maxtemp = float(temp)
        city_maxlist.append([maxtemp, line[0])
    maxtempcity = 0.0
    for city in city_maxlist:
        if city[0] >= maxtempcity:
            maxtempcity = city[0]
    citylist = []
    for line in data:
        for temp in line:
            if temp == maxtempcity:
                citylist.append(line[0])
    return (maxtempcity, citylist)

Answer 1

Your main problem is that "data" is an iterator, so you can iterate over it only once (your second loop over data does not loop at all).

data = list(csv.reader(file))

should help. Then as Hans Then noticed, you did not provide the code you execute, so I let you correct your tests in the second loop over data.