試圖從Python代碼中使用python刮取數據

Question

我一直在爲一個網站製作一個網絡抓取工具，我想從一個html表格中使用.findall提取所有節點編號，或者可以工作的東西，但我正在努力獲取它，我不斷地收到錯誤，我顯然沒有把正確的標籤。

誰能幫助，HTML代碼如下所示

</div> 

<table class="dataTable" cellpadding="5" cellspacing="0" rules="all" border="1" id="ctl00_ContentPlaceHolder1_dgNodes" style="border-collapse:collapse;"> 
    <tr class="header noBreak"> 
     <td>&nbsp;</td><td><a href="javascript:__doPostBack('ctl00$ContentPlaceHolder1$dgNodes$ctl00$ctl00','')">Node Name</a></td><td><a href="javascript:__doPostBack('ctl00$ContentPlaceHolder1$dgNodes$ctl00$ctl01','')">Description</a></td><td><a href="javascript:__doPostBack('ctl00$ContentPlaceHolder1$dgNodes$ctl00$ctl02','')">MAC Address</a></td><td><a href="javascript:__doPostBack('ctl00$ContentPlaceHolder1$dgNodes$ctl00$ctl03','')"></a> 
       <a href="javascript:__doPostBack('ctl00$ContentPlaceHolder1$dgNodes$ctl00$liNodeRoleHeader','')" id="ctl00_ContentPlaceHolder1_dgNodes_ctl00_liNodeRoleHeader">Node Role</a> 
      </td><td><a href="javascript:__doPostBack('ctl00$ContentPlaceHolder1$dgNodes$ctl00$ctl04','')">Firmware</a></td><td> 
       <a href="javascript:__doPostBack('ctl00$ContentPlaceHolder1$dgNodes$ctl00$lbUptimeHeader','')" id="ctl00_ContentPlaceHolder1_dgNodes_ctl00_lbUptimeHeader">Uptime</a> 
      </td><td><a href="javascript:__doPostBack('ctl00$ContentPlaceHolder1$dgNodes$ctl00$ctl05','')">Users</a></td> 
    </tr><tr onmouseover="this.className = 'highlightedRow';" onmouseout="this.className = 'normalRow';" onclick="GoToNodePage('522');" style="height:18px;"> 

我需要提取上的代碼的最後一行和所有其他gotonodepage號數522，但我不能弄清楚，任何幫助表示讚賞。我也想把提取的數字放入後面使用的列表中。

r2 = s2.get(webpage) 
bsobjswap = BeautifulSoup(r2.content) 

listy = [] 
for link in bsobjswap.findall('tr'): 
    if 'onclick' in link.attrs: 
     listy.append(link) 
print (listy) 

誤差 在bsobjswap.findall鏈接（ 'TR'）： 類型錯誤： 'NoneType' 對象不是可調用

Answer 1

嘗試是這樣的：

from bs4 import BeautifulSoup 

xml = """<table class="dataTable" cellpadding="5" cellspacing="0" rules="all" border="1" id="ctl00_ContentPlaceHolder1_dgNodes" style="border-collapse:collapse;"> 
    <tr class="header noBreak"> 
     <td>&nbsp;</td><td><a href="javascript:__doPostBack('ctl00$ContentPlaceHolder1$dgNodes$ctl00$ctl00','')">Node Name</a></td><td><a href="javascript:__doPostBack('ctl00$ContentPlaceHolder1$dgNodes$ctl00$ctl01','')">Description</a></td><td><a href="javascript:__doPostBack('ctl00$ContentPlaceHolder1$dgNodes$ctl00$ctl02','')">MAC Address</a></td><td><a href="javascript:__doPostBack('ctl00$ContentPlaceHolder1$dgNodes$ctl00$ctl03','')"></a> 
       <a href="javascript:__doPostBack('ctl00$ContentPlaceHolder1$dgNodes$ctl00$liNodeRoleHeader','')" id="ctl00_ContentPlaceHolder1_dgNodes_ctl00_liNodeRoleHeader">Node Role</a> 
      </td><td><a href="javascript:__doPostBack('ctl00$ContentPlaceHolder1$dgNodes$ctl00$ctl04','')">Firmware</a></td><td> 
       <a href="javascript:__doPostBack('ctl00$ContentPlaceHolder1$dgNodes$ctl00$lbUptimeHeader','')" id="ctl00_ContentPlaceHolder1_dgNodes_ctl00_lbUptimeHeader">Uptime</a> 
      </td><td><a href="javascript:__doPostBack('ctl00$ContentPlaceHolder1$dgNodes$ctl00$ctl05','')">Users</a></td> 
    </tr><tr onmouseover="this.className = 'highlightedRow';" onmouseout="this.className = 'normalRow';" onclick="GoToNodePage('522');" style="height:18px;">""" 

soup = BeautifulSoup(xml) 
print([i.get('onclick') for i in soup.findAll('tr', attrs={'onclick':True})]) 

這將返回["GoToNodePage('522');"]

從這裏你可以用正則表達式提取數字例如

print([re.findall("\d+", i.get('onclick')) for i in soup.findAll('tr', attrs={'onclick':True})]) 

這將返回[['522']]