Question

尝试将数据解析为列表列表时遇到问题。我正试图抓取有关部门及其主题的信息。但是，由于每个部门都有不同数量的主题，我需要创建一个列表列表，以便稍后将数据链接在一起。我设法导航索引错误，问题似乎来自编译主题列表。

from lxml import html
import requests

page = requests.get('URL')

page_source_code = html.fromstring(page.text)


departments_list = []
subject_list = []

for dep in range(1,3):
    departments = page_source_code.xpath('tag'
                                         +str(dep)+']tag/text()')

    ### print(dep, departments)
    if departments == []:
        pass
    else:
        departments_list.append(departments[0])


    for sub in range(1,20):
        subjects = page_source_code.xpath('tag'
                                      +str(dep)+']tag'
                                      +str(sub)+']tag/text()')
        ### print(sub, subjects)
        if subjects == []:
            pass
        else:
            subject_list.append(subjects[0])

print('Department list ------ ', len(departments_list), departments_list, '\n')
print('Subject list ------ ', len(subject_list), subject_list)

我的输出如下：

Department list ------  2 ['Department_1', 'Department_2'] 

Subject list ------  7 ['Subject_1'(dep_1), 'Subject_2 '(dep_1), 'Subject_3 '(dep_1), 'Subject_4'(dep_1), 'Subject_5'(dep_2), 'Subject_6 '(dep_2), 'Subject_7 '(dep_2)']

此代码似乎将所有主题放入一个列表中。我希望如下：

Subject list ------  7 [['Subject_1'(dep_1), 'Subject_2 '(dep_1), 'Subject_3 '(dep_1), 'Subject_4'(dep_1)], ['Subject_5'(dep_2), 'Subject_6 '(dep_2), 'Subject_7 '(dep_2)']]

Answer 1

您需要为主题列表全局添加两个列表并找出subject [0]字符串中的'dep_1'或'dep_2'字样。

     #declare the list for subject 
     sub_list1 = [] sub_list2 = []

     #this code is under the second for loop
     if subjects.find('dep_1') == -1 :
         sub_list2.append(subjects[0])
     else:
         sub_list1.append(subjects[0])

     #Please remove the subjectList.append statement 
     #from second for loop
     #and put it end of both loop like that .
     subjectList = [sub_list1,sub_list2]

将数据解析为列表列表

1 个答案: