python第三方库使用经验

requests

官方中文帮助文档：
1. requests1.1.0快速上手
2. requests1.1.0高级用法

Beautifulsoup

官方中文帮助文档：
BeautifulSoup
使用BeautifulSoup的例子

def regUrls():
    html_file = open('E:\WORK_FILE\Python\Python2\userful\coursera\coursera.html').read()
    soup = BeautifulSoup(html_file,'lxml')
    course_item_header_div_tags = soup.find_all('div',class_='course-item-list-header')
    '''result = {}
    count = 0
    for div_tag in course_item_header_div_tags:
        count += 1
        week_course_name = str(count) + '-week-' + div_tag.h3.contents[1][2:].encode('utf8')
        result[week_course_name] = {}
        ul_tag = div_tag.next_sibling
        li_tags = ul_tag.find_all('li')
        for li_tag in li_tags:
            lecture_name = li_tag.a.string.encode('utf8')
            #print lecture_name
            lecture_name = re.search(r'\b[a-zA-Z ]+\b',lecture_name).group(0)
            lecture_view_link = li_tag.a.get('data-modal-iframe').encode('utf8')
            result[week_course_name][lecture_name] = []
            result[week_course_name][lecture_name].append(lecture_view_link)
            for a_tag in li_tag.div.find_all('a'):
                href = a_tag.get('href').encode('utf8')
                if 'download.mp4' not in href:
                    result[week_course_name][lecture_name].append(href)

    return result

def genXml(res_dic):
    week_indent = 4
    week_name_indent = 4 * 2
    lecture_indent = 4 * 2
    lecture_name_indent = 4 * 3
    url_indent = 4 * 3
    xml = ''
    xml += '\n'
    week_name_keys = res_dic.keys()
    week_name_keys.sort(key=lambda item:int(item[:item.find('-')]))
    for week_name in week_name_keys:
        xml += '\n' + ' ' * week_indent + ''
        xml += '\n' + ' ' * week_name_indent + '%s' % week_name
        lectures = res_dic[week_name]
        lecture_name_keys = lectures.keys()
        lecture_name_keys.sort()
        #print lecture_name_keys
        for lecture_name in lecture_name_keys:
            xml += '\n' + ' ' * lecture_indent + ''
            xml += '\n' + ' ' * lecture_name_indent + '%s' % lecture_name
            urls = lectures[lecture_name]
            for url in urls:
                xml += '\n' + ' ' * url_indent + '' % url
            xml += '\n' + ' ' * lecture_indent + ''
        xml += '\n' + ' ' * week_indent + ''
    xml += '\n'
    with open('course.xml','w') as fd:
        fd.write(xml)
    return xml

BeautifulSoup使用总结

1. 搜索
   bs提供了丰富的搜索方法：

   • find_all( name , attrs , recursive , text , **kwargs )
     name:标签名
     attrs:{‘attrname’:’value1 value2’}
     text:文本
     **kwargs：可以是属性名和值，比如href=’http://www.example.com’
     支持回调函数，正则表达式，过滤器，字符串
   • find
   • find_parents
   • find_parent
   • find_next_siblings
   • find_next_sibling
   • find_previous_siblings
   • find_previous_sibling
   • find_all_next
   • find_next
   • find_all_previous
   • find_previous

2. 遍历文档树

   • 子节点
     
     • tag的名字
     • .contents 和 .children
     • .descendants
     • .string
     • .strings 和 stripped_strings
   • 父节点
     
     • .parent
     • .parents
   • 兄弟节点
     
     • .next_sibling 和 .previous_sibling
     • .next_siblings 和 .previous_siblings
   • 回退和前进
     
     • .next_element 和 .previous_element
     • .next_elements 和 .previous_elements

3. 修改文档树

   • 修改tag的名称和属性
   • 修改 .string
   • append()
   • BeautifulSoup.new_string() 和 .new_tag()
   • insert()
   • insert_before() 和 insert_after()
   • clear()
   • extract()
   • decompose()
   • replace_with()
   • wrap()
   • unwrap()

chardet

编码检测模块

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