值我是新来的Python和我正在写一个webscraper,以查找<td>
行的HTML表:检查是否存在
# open CSV with URLS to scrape
csv_file = csv.reader(open('urls.csv', 'rb'), delimiter=',')
names = []
for data in csv_file:
names.append(data[0])
for name in names:
html = D.get(name);
html2 = html
param = '<br />';
html2 = html2.replace("<br />", " | ")
print name
c = csv.writer(open("darkgrey.csv", "a"))
for row in xpath.search(html2, '//table/tr[@class="bgdarkgrey"]'):
cols = xpath.search(row, '/td')
c.writerow([cols[0], cols[1], cols[2], cols[3], cols[4]])
它所做的是从4表中获取价值'<td>'
问题是,有些桌子没有cols[2]
,cols[3]
或cols[4]
有没有办法,我可以检查这些是否存在?
感谢
有点偏离主题,但是你真的想追加到“darkgrey.csv”吗?如果我在哪里,我会在全局范围内用“w”打开该文件,以防止在您再次测试该脚本时它增长到inf。还请确保关闭它! – RickyA