import urllib,urllib2,sys,osfrom BeautifulSoup import BeautifulSoupimport itertools,reurl_i =1pic_num = 1#自己定義的引號格式轉換函數def _en_to_cn(str):  obj = itertools.cycle(['“','”'])  _obj = lambda x: obj.next()  return re.sub(r"['/"]",_obj,str)if __name__ == '__main__':  #下載連續3個網頁的視頻  while url_i <= 3:    webContent = urllib2.urlopen("http://news.youku.com/focus/index/_page26716_" + str(url_i) + ".html")    data = webContent.read()    #利用BeautifulSoup讀取視頻列表網頁數據    soup = BeautifulSoup(data)    print "-------------------------Page " + str(url_i) + "-------------------------"    #獲得相應頁面的視頻thumbnail和title的list    tag_list_thumb = soup.findAll('li','v_thumb')    tag_list = soup.findAll('li', "v_title")    for item in tag_list:      #通過每個thumbnail中的herf導向視頻播放頁面      web_video_play = urllib2.urlopen(item.a['href'])      data_vp = web_video_play.read()      #利用BeautifulSoup讀取視頻播放網頁數據      soup_vp = BeautifulSoup(data_vp)      #找到“下載”對應的鏈接      tag_vp_list = soup_vp.findAll('a', id = 'fn_download')      for item_vp in tag_vp_list:        #將下載鏈接保存到url_dw中        url_dw = '"' + item_vp['_href'] + '"'        print item.a['title'] + ": " + url_dw        #調用命令行運行iku下載視頻，需將iku加入環境變量        os.system("iku " + url_dw)    #保存每個視頻的thumbnail    for item_thumb in tag_list_thumb:      urllib.urlretrieve(item_thumb.img['src'], "E://下載視頻//thumbnails//" + str(pic_num) + "." +                _en_to_cn(item_thumb.img['title']) + ".jpg")      pic_num += 1    print "--------------------------------------------------------------"    print "--------Page " + str(url_i) + "'s video thumbnails have been saved!"    url_i += 1