数据写入csv

import csv


data_list = []
for tr in tr_list:
    lt = []
    lt.append(tr.xpath('//td[1]/text()')[0])
    lt.append(tr.xpath('//td[2]/text()')[0])
    lt.append(tr.xpath('//td[3]/text()')[0])
    data_list.append(lt)

with open('daletou.csv', 'a') as f:
    writer = csv.writer(f)
    writer.writerow(['title1', 'title2', 'title3'])
    writer.writerows(data_list)