本文实例讲述了Python爬取国外天气预报网站的方法。分享给大家供大家参考。具体如下：

crawl_weather.py如下：

#encoding=utf-8 import httplib import urllib2 import time from threading import Thread import threading from Queue import Queue from time import sleep import re import copy lang = "fr" count = 0 class Location: # Location(False, "中国", "北京", "zh") # Location(True, "", "亚洲", "zh") def __init__(self, is_beyond_country, country_name, loc_name, lang): self.country_name = country_name self.loc_name = loc_name self.lang = lang self.is_beyond_country = is_beyond_country prn_lock = threading.RLock() def GetLocationURLs(url, recursive): global count if url.find("weather-forecast") != -1: count = count + 1 if count % 500 == 0: prn_lock.acquire() print "count:%d" % (count) prn_lock.release() return [url] page = urllib2.urlopen(url).read() time.sleep(0.01) #"<h6><a href="http://www.accuweather.com/zh/browse-locations/afr"><em>Africa</em></a></h6>" pattern = "<h6><a href="(.*)"><em>(.*)</em></a></h6>" locs = re.findall(pattern, page) locs = [(url, name) for url, name in locs if url.find("browse-locations") != -1 or url.find("weather-forecast") != -1] if not recursive: urls = [url for url, name in locs] return urls urls = [] for _url, _name in locs: lst = GetLocationURLs(_url, True) urls.extend(lst) return urls #entry_url = "http://www.accuweather.com/zh/browse-locations" entry_url = "http://www.accuweather.com/%s/browse-locations/eur/fr" % (lang) #regions = ["afr", "ant", "arc", "asi", "cac", "eur", "mea", "nam", "ocn", "sam"] #regions = ["eur"] #region_urls = [ "%s/%s" % (entry_url, reg) for reg in regions] #region_urls = ["http://www.accuweather.com/zh/browse-locations/eur/fr"] sub_urls = GetLocationURLs(entry_url, False) print len(sub_urls) print sub_urls q = Queue() location_urls = [] ThreadNum = 5 lock = threading.RLock() for url in sub_urls: q.put(url) def working(): while True: url = q.get() lst = GetLocationURLs(url, True) print "%s %d urls " % (url, len(lst)) lock.acquire() location_urls.extend(lst) lock.release() q.task_done() for i in range(ThreadNum): t = Thread(target=working) t.setDaemon(True) t.start() q.join() fp = open('locations.txt', "w") fp.write("n".join(location_urls)) fp.close() #for url in location_urls: # print url #location_urls = GetLocationURLs(entry_url) ''' def Fetch(url): try: print url web_path = url[0] local_name = url[1] print "web_path:", web_path print "local_name:", local_name sContent = urllib2.urlopen(web_path).read() savePath = "D:CourseNLP_Manning%s" % (local_name) print savePath file = open(savePath,'wb') file.write(sContent) file.close() print savePath + " saved"; except: pass; def working(): while True: url = q.get() Fetch(url) sleep(10) q.task_done() #root_url = "https://class.coursera.org/nlp/lecture/index?lecture_player=flash" root_url = "https://class.coursera.org/nlp/lecture/index?lecture_player=flash" page = urllib2.urlopen(root_url).read() for i in range(NUM): t = Thread(target=working) t.setDaemon(True) t.start() urls = copy.deepcopy(ppt_urls) urls.extend(srt_urls) urls.extend(video_urls) print len(ppt_urls) print len(srt_urls) print len(video_urls) print len(urls) for url in urls: q.put(url) q.join() ''' ''' root_url = "http://www.accuweather.com/zh/cn/andingmen/57494/weather-forecast/57494" page = urllib2.urlopen(root_url).read() print page '''

FetchLocation.py如下：

#encoding=utf-8 import sys import httplib import urllib2 import time from threading import Thread import threading from Queue import Queue from time import sleep import re import copy from xml.dom import minidom import HTMLParser import datetime q = Queue() locks = [threading.RLock() for i in range(2)] ThreadNumber = 20 locations = {} conds = {} def FindCountryBreadCrumbs(page): lines = page.splitlines() count = 0 start = -1 opened = False for line in lines: if line.find("<ul id="country-breadcrumbs">") != -1: start = count opened = True if opened and line.find("</ul>") != -1: end = count opened = False count = count + 1 return "n".join(lines[start: (end + 1)]) def GetText(nodelist): rc = [] for node in nodelist: if node.nodeType == node.TEXT_NODE: rc.append(HTMLParser.HTMLParser().unescape(node.data)) return ''.join(rc) def FindCondition(page): pat = "<span>(.*" cds = re.findall(pat, page) cds = [HTMLParser.HTMLParser().unescape(cd).encode("utf-8") for cd in cds] return cds def ExtractInfo(url): try: page = urllib2.urlopen(url).read() except Exception, e: return [] text = FindCountryBreadCrumbs(page) text = HTMLParser.HTMLParser().unescape(text) dom = minidom.parseString(text.encode("utf-8")) locs = [] lis = dom.getElementsByTagName("li") for li in lis: adr_list = li.getElementsByTagName("a") if adr_list: locs.append(GetText(adr_list[0].childNodes).encode("utf-8")) strs = li.getElementsByTagName("strong") if strs: locs.append(GetText(strs[0].childNodes).encode("utf-8")) cds = FindCondition(page) return locs, cds def AddMap(lst, m): for x in lst: if m.get(x) == None: m[x] = 1 def working(): while True: urls = q.get() #print len(urls) m = {} m2 = {} count = 0 for url in urls: count = count + 1 #print "%d/%d" % (count, len(urls)) locs, cds = ExtractInfo(url) AddMap(locs, m) AddMap(cds, m2) locks[1].acquire() AddMap(m.keys(), locations) AddMap(m2.keys(), conds) locks[1].release() q.task_done() def main(): if len(sys.argv) < 2: exit() loc_path = sys.argv[1] fp = open(loc_path, "r") urls = [line.strip() for line in fp] fp.close() #urls = urls[0:1000] blocks = len(urls) / ThreadNumber + 1 for start in range(0, len(urls), blocks): end = start + blocks if end > len(urls): end = len(urls) q.put(urls[start:end]) for i in range(ThreadNumber): t = Thread(target=working) t.setDaemon(True) t.start() q.join() fp = open("location_name.fr", "w") fp.write("n".join(locations.keys())) fp.close() fp = open("conditions.fr", "w") fp.write("n".join(conds.keys())) fp.close() if __name__ == '__main__': main()

希望本文所述对大家的python程序设计有所帮助。