import csv

import lxml.html

class ScrapcCallback:

    def __init__(self):

        self.witer=csv.writer(open("test.csv","a"))

        self.fields =("name","age","gred")

        self.witer.writerow(self.fields)

tree= lxml.html.fromstring(html)

tree.cssselect('#content > p ')

class my_dict:

    def __setitem__(self, folder, result):

        print(bool(folder))

        if not  folder:

            os.mkdir(folder)

        with open("test","wb") as fp:

            fp.write(pickle.dumps(result))

    def __getitem__(self, item):

        if os.path.exists(item):

            with open(item,"rb") as fp:

                return  pickle.load(fp)

#先实例化在使用

s = b"hello world"

print(s, type(s))

# 解码

s_1 = s.decode('utf-8')

print(s_1, type(s_1))

# 编码

s_2 = s_1.encode("utf-8")

print(s_2, type(s_2))

string="{'name':'tom'}"

string = '{"name":"tom"}'