如何使用 python 从网页中提取数据

Question

有人可以指出我做错了什么吗？

Enter Item name:Rockfish Traceback (most recent call last): File "C:\Users\partn_000\Desktop\sarvesh\Python Source Code\working\jellyneoscraper.py", line 45, in search(br, ITEMNAME) File "C:\Users\partn_000\Desktop\sarvesh\Python Source Code\working\jellyneoscraper.py", line 33, in search increment = increment[0] IndexError: list index out of range

这是我写的代码

#Library Imports
import mechanize
import cookielib
import re
import sys
import time
import os.path
from operator import itemgetter
import ctypes
ctypes.windll.kernel32.SetConsoleTitleA("test")


def init_browser():
    br = mechanize.Browser()
    br.set_handle_equiv(True)
    br.set_handle_redirect(True)
    br.set_handle_referer(True)
    br.set_handle_robots(False)
    br.set_handle_refresh(mechanize._http.HTTPRefreshProcessor(), max_time=1)
    br.addheaders = [('User-agent', 'Mozilla/5.0 (Windows NT 6.2; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/36.0.1985.125 Safari/537.36')]
    cj = cookielib.LWPCookieJar()
    br.set_cookiejar(cj)

    return br


def search(br, ITEMNAME):
    datapage = br.open('http://items.jellyneo.net/index.php?go=show_items&name=' +ITEMNAME +'&name_type=exact&desc=&cat=0&specialcat=0&status=0&rarity=0&sortby=name&numitems=20')
    f = open('search.html', 'w')
    f.write(datapage.read())
    f.close()
    value = re.findall('style="font-weight:bold;">(.+) NP</a></td>"',datapage.read())  #(.+) is replaced in place of required value
    value = value[0].replace(",","")
    value = int(value)
    print value
#http://items.jellyneo.net/index.php?go=show_items&name=Rockfish&name_type=exact&desc=&cat=0&specialcat=0&status=0&rarity=0&sortby=name&numitems=20


#('style="font-weight:bold;"> (.+) NP</a>"',search.read())


ITEMNAME = raw_input('Enter Item name:eg. Rockfish')

br = init_browser()
search(br, ITEMNAME)

Answer 1

在您的搜索方法中，您阅读了整个页面并将其保存到文件中，然后你尝试重新阅读它执行你的正则表达式但是你已经在页面的末尾所以它 returns 空字符串。你应该像这样再次阅读之前添加 datapage.seek(0)：

datapage = br.open('http://items.jellyneo.net/index.php?go=show_items&name=' +ITEMNAME +'&name_type=exact&desc=&cat=0&specialcat=0&status=0&rarity=0&sortby=name&numitems=20')
f = open('search.html', 'w')
f.write(datapage.read())
f.close()
datapage.seek(0)
value = re.findall('style="font-weight:bold;">(.+) NP</a></td>"',datapage.read())  #(.+) is replaced in place of required value
value = value[0].replace(",","")
value = int(value)

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