Question

我正在为一个班级做一个程序，我们的老师给了我们使用的csv.DictReader函数，但没有解释它。它只是一个更大的计划的一部分。我正在尝试阅读天气数据的电子表格。它有几个名为TemperatureF，VisibilityMPH等的列。我需要在电子表格的一列中读取并将其值作为列表放入字典中，其中键是列名。我这样做了，但是当我尝试循环并为第二列进行操作时，我的列表没有填满。这是我的代码和输出。

import csv

def read_file(filename, col_list):
    with open(filename, 'r') as f:
        reader = csv.DictReader(f)

        final_dict = {}
        x = 0
        while x < len(col_list):

            print 'X IS ' + str(x)
            this_list = []

            print 'list before adding stuff: ' #test

            print this_list   #test

            for row in reader:
                this_list.append([row[col_list[x]]])

            print 'list after adding stuff' #test

            print this_list   #test

            final_dict[col_list[x]] = this_list

            x += 1
        print final_dict

    def main():
        read_file('weather.csv', ['VisibilityMPH', 'TemperatureF'])


    if __name__ == "__main__":
        main()

输出：

Answer 1

你可能想要的是：

import csv

def read_file(filename, col_list):
    with open(filename, 'r') as f:
        reader = csv.DictReader(f)

        final_dict = {}
        x = 0

        while x < len(col_list):

            print 'X IS ' + str(x)
            this_list = []

            print 'list before adding stuff: ' #test

            print this_list   #test

            for row in reader:
                this_list.append([row[col_list[x]]])

            print 'list after adding stuff' #test

            print this_list   #test

            final_dict[col_list[x]] = this_list

            x += 1

        print final_dict

def main():
    read_file('weather.csv', ['VisibilityMPH', 'TemperatureF'])


if __name__ == "__main__":
    main()

注意你的while块有不正确的缩进。但实际上可以改进代码片段。

import csv

def read_file(filename, col_list):
    with open(filename, 'r') as f:
        reader = csv.DictReader(f)

        final_dict = { col_name: [] for col_name in col_list }

        for row in reader:
            for col_name in col_list:
                final_dict[col_name].append(row[col_name])

        print final_dict

def main():
    read_file('weather.csv', ['VisibilityMPH', 'TemperatureF'])


if __name__ == "__main__":
    main()

如何使用csv.DictReader

1 个答案: