python调用requests时发生too many values to unpack (expected 2)错误

Question

python调用requests时发生too many values to unpack (expected 2)错误

问题遇到的现象和发生背景

编程时调用requests发生错误

错误代码

def mainf():
    headerses = {"User-Agent","Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/105.0.0.0 Safari/537.36"}
    urls='http://www.centrechina.com/news/jiaodian/'
    response = requests.get(urls,headerses)
    html_data=response.text
    soupClass=BeautifulSoup(html_data,"lxml")
    news_url_get=[]
    a=soupClass.select('.ajax-load-con h2 a')       #选中a标签
    for i,x in a:
        news_url_get.append(i['href'])       #提取标签并加到列表中
    print(news_url_get)
mainf()

运行结果及报错内容

pycharm:

Traceback (most recent call last):
  File "G:\python_project\test_requests.py", line 42, in <module>
    today_news()
  File "G:\python_project\test_requests.py", line 32, in today_news
    response = requests.get(url,headers)
  File "C:\Users\David Chen\AppData\Roaming\Python\Python39\site-packages\requests\api.py", line 73, in get
    return request("get", url, params=params, **kwargs)
  File "C:\Users\David Chen\AppData\Roaming\Python\Python39\site-packages\requests\api.py", line 59, in request
    return session.request(method=method, url=url, **kwargs)
  File "C:\Users\David Chen\AppData\Roaming\Python\Python39\site-packages\requests\sessions.py", line 573, in request
    prep = self.prepare_request(req)
  File "C:\Users\David Chen\AppData\Roaming\Python\Python39\site-packages\requests\sessions.py", line 484, in prepare_request
    p.prepare(
  File "C:\Users\David Chen\AppData\Roaming\Python\Python39\site-packages\requests\models.py", line 368, in prepare
    self.prepare_url(url, params)
  File "C:\Users\David Chen\AppData\Roaming\Python\Python39\site-packages\requests\models.py", line 474, in prepare_url
    enc_params = self._encode_params(params)
  File "C:\Users\David Chen\AppData\Roaming\Python\Python39\site-packages\requests\models.py", line 121, in _encode_params
    for k, vs in to_key_val_list(data):
ValueError: too many values to unpack (expected 2)

vscode:

我想要达到的结果

正确输出爬取内容

求解决，谢谢！

Answer 1

一、headers应该是字典，你这里写成了集合，需要把逗号改成冒号
二、requests.get的用法要使用关键字传参而不是位置传参，需要改成response = requests.get(url=urls,headers=headerses)
三、返回的a变量的内容确定有两个内容吗？for i,x in a: 改成 for i in a: 就可以运行了