Question

我有一个任务要做，我被卡住了，因为我所做的一切似乎都不起作用。

所以我必须要csv文件。首先调用people_file，它包含标题行：id，名称，姓氏。以及包含id，person_id，网站的visits_file。我必须编写一个称为merge的函数，该函数以文件作为参数（均为StrionIO类型）获取文件，并返回字典列表以及每个用户的访问次数：

[ {
 "id": (person's id),
 "name": (person's name),
 "surname": (person's surname),
 "visits": (number of visits)
 } ]

我想到了这个，但我不知道我的错误在哪里。

import io

def merge(persons_file,visits_file):
    line_counter = 0
    return_list = []
    list_of_person_ids = []
    visits = 0

    for row in visits_file:
        if line_counter == 0:
            line_counter+=1
            continue
        list_of_person_ids.append(row.split(',')[1])

    line_counter = 0

    for row in persons_file:
        if line_counter == 0:
            line_counter+=1
            continue
        help_dict = {}
        split_row = row.split(',')
        help_dict['id'] = split_row[0]
        help_dict['name'] = split_row[1]
        help_dict['surname'] = split_row[2][:len(split_row[2])-1]
        if split_row[0] in list_of_person_ids:
            visits = list_of_person_ids.count(split_row[0])
        help_dict['visits'] = str(visits)
        return_list.append(help_dict)
        visits=0
    return return_list

file1 = open('persons_file.csv' , mode='r')
file2 = open('visits_file.csv' , mode='r')
persons_file_arg = io.StringIO(file1.read())
visits_file_arg = io.StringIO(file2.read())

list_of_visits = merge(persons_file_arg,visits_file_arg)
for i in list_of_visits:
    print(i)
file1.close()
file2.close()

如果有人能帮助我，我会很高兴。

Answer 1

出了什么问题？是不是您所期望的输出，还是您遇到异常？您的代码似乎应该可以达到所需的结果，但是我有几点建议可以简化事情。

查看collections.Counter，然后可以调用count_of_visits_by_person_id = Counter(list_of_person_ids)以获取以下形式的结果： {person_id: number_of_visits, ...}。然后，您可以使用它简单地在下一个for循环中查找访问次数。例如：

from collections import Counter

...

count_of_visits_by_person_id = Counter(list_of_person_ids)

for row in persons_file:
    if line_counter == 0:
        line_counter += 1
        continue

    help_dict = {}
    split_row = row.split(',')

    help_dict['id'] = split_row[0]
    help_dict['name'] = split_row[1]
    help_dict['surname'] = split_row[2][:-1]  
   # [:len(split_row[2]) - 1] is equivalent to [:-1]
   # I assume you are stripping whitespace from the right side,
   # which can also be accomplished using split_row[2].rstrip()

    if split_row[0] in count_of_visits_by_person_id:
        visits = count_of_visits_by_person_id[split_row[0]]
    else:
        visits = 0
    help_dict['visits'] = str(visits)

    return_list.append(help_dict)

打开文件通常更简单，更安全的方法是使用with语句。这是一个示例：

with open('visits_file.csv', mode='r') as visits_file:
   row = visits_file.readline()
   while row:
       row = visits_file.readline()  # Skips the first line
       list_of_person_ids.append(row.split(',')[1])

将两个csv文件合并到词典列表中

1 个答案: