csv文件没有数据，刚开始学习爬虫，这代码是在csdn找到的，帮我看看为什么实现不了csv文件有数据，感谢
import requests
from lxml import etree
import time
import random
import csv
import pandas as pd
def get_target(keyword, page,saveName):
result = pd.DataFrame()
for i in range(1, page + 1):
headers = {
'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.116 Safari/537.36'}
url = 'https://search.bilibili.com/all?keyword={}&from_source=nav_suggest_new0&page={}'.format(keyword, i)
html = requests.get(url.format(i), headers=headers)
bs = etree.HTML(html.text)
items = bs.xpath('//li[@class = "video-item matrix"]')
for item in items:
video_url = item.xpath('div[@class = "info"]/div/a/@href')[0].replace("//","") #每个视频的来源地址
title = item.xpath('div[@class = "info"]/div/a/@title')[0] #每个视频的标题
region = item.xpath('div[@class = "info"]/div[1]/span[1]/text()')[0].strip('\n ') #每个视频的分类版块如动画
view_num = item.xpath('div[@class = "info"]/div[3]/span[1]/text()')[0].strip('\n ') #每个视频的播放量
danmu = item.xpath('div[@class = "info"]/div[3]/span[2]/text()')[0].strip('\n ') #弹幕
upload_time = item.xpath('div[@class = "info"]/div[3]/span[3]/text()')[0].strip('\n ') # 上传日期
up_author = item.xpath('div[@class = "info"]/div[3]/span[4]/a/text()')[0].strip('\n ') #up主
df = pd.DataFrame({'region': [region],'title': [title], 'view_num': [view_num], 'danmu': [danmu], 'upload_time': [upload_time], 'up_author': [up_author], 'video_url': [video_url]})
result = pd.concat([result, df])
time.sleep(random.random() + 1)
print('已经完成b站第 {} 页爬取'.format(i))
saveName = saveName + ".csv"
result.to_csv(saveName, encoding='utf-8-sig',index=False) # 保存为csv格式的文件
return result
if __name__ == "__main__":
keyword = input("请输入要搜索的关键词：")
page = int(input("请输入要爬取的页数："))
saveName = input("请输入要保存的文件名：")
get_target(keyword, page,saveName)
