为什么python3 使用list.append(元素)。元素前后类型变了？

Question

        print(type(type1[0].string))
        ulist2.append([type1[0].sting, type1[1].sting, type1[2].sting, type1[3].sting])
        print(type(type1[0].sting))

输出：

<class 'bs4.element.NavigableString'>
<class 'NoneType'>

完整代码：

import requests
from bs4 import BeautifulSoup
import bs4

def get_html(url):
    try:
        r = requests.get(url)
        r.raise_for_status()
        r.encoding = r.apparent_encoding
        return r.text
    except Exception as f:
        print("fault:{}".format(f))
        return ''

def parser_html(ulist, html):

    soup = BeautifulSoup(html,'html.parser')
    n = 0
    for tag in soup.tbody.children:
        n += 1
        ulist2 = []
        if isinstance(tag, bs4.element.Tag):

            # print(tag)
            # print(type(tag))
            type1 = tag.find_all('td')
            print(type(type1))
            print(type1)
            print(type1[0].string)
            print(type1[1].string)
            print(type(type1[0].string))
            # for tag2 in type1:
            #
            #     ulist2.append(tag2.string)
            ulist2.append([type1[0].sting, type1[1].sting, type1[2].sting, type1[3].sting])
            print(type(type1[0].sting))
            # ulist2 = ulist2[:4]
            print(ulist2)
            ulist = ulist + ulist2
            print(ulist)
        if n > 10:

            return ulist
    return ulist

            # ulist.append([tag[0].string, tag[1].string, tag[2].string])


def print_info(ulist, num):
    print(ulist)
    for i in range(num):

        print('{0:<10}\t{1:{4}<25}\t{2:<10}\t{3:<10}'.format(ulist[i][0],ulist[i][1], ulist[i][2], ulist[i][3], chr(12288)))


def main():
    ulist = []
    url = "http://www.zuihaodaxue.com/Greater_China_Ranking2019_0.html"
    html = get_html(url)
    parser_html(ulist, html)
    print_info(ulist, 5)



if __name__ == "__main__":
    main()

Answer 1

代码单词敲错了。

print(type(type1[0].sting)) ----> print(type(type1[0].string))

Answer 2

sting还行...我倒是想问为啥没报错