day22-python之模块

1.os

 import os

 # print(os.getcwd())
 # os.chdir("..")
 # print(os.getcwd())

 # os.makedirs('dirname1/dirname2')
 # os.removedirs("dirname1/dirname2")
 # print(os.listdir())
 # print(os.stat("test.py"))

 # print(os.system("dir"))
 #
 # print(os.path.split(r"C:\Users\Administrator\脱产三期\day22\sss.py"))
 # print(os.path.dirname(r"C:\Users\Administrator\脱产三期\day22\sss.py"))
 # print(os.path.basename(r"C:\Users\Administrator\脱产三期\day22\sss.py"))
 a="C:\Users\Administrator"
 b="脱产三期\day22\sss.py"
 #
 os.path.join(a,b)#  路径拼接

2.xml解析

 # import xml.etree.ElementTree as ET

 # tree = ET.parse("../day22/xml_lesson.xml")
 # root = tree.getroot()
 # print(root.tag)

 # for i in root:
 #
 #     # print(i.tag)
 #     # print(i.attrib)
 #     for j in i:
 #         # print(j.tag)
 #         # print(j.attrib)
 #         print(j.text)

 # # 遍历xml文档
 # for child in root:
 #     # print(child.tag, child.attrib)
 #     for i in child:
 #         print(i.tag, i.text)

 # 只遍历year 节点
 # for node in root.iter('year'):
 #     print(node.tag, node.text)
 # # ---------------------------------------

 # import xml.etree.ElementTree as ET
 #
 # tree = ET.parse("../day22/xml_lesson.xml")
 # root = tree.getroot()

 # 修改
 # for node in root.iter('year'):
 #     new_year = int(node.text) + 1
 #     node.text = str(new_year)
 #     node.set("updated", "no")
 # #
 # tree.write("../day22/xml_lesson.xml")
 #
 # 删除node
 # for country in root.findall('country'):
 #     rank = int(country.find('rank').text)
 #     if rank > 50:
 #         root.remove(country)
 #
 # tree.write('output.xml')

 import xml.etree.ElementTree as ET

 new_xml = ET.Element("namelist")
 #
 name = ET.SubElement(new_xml, "name", attrib={"enrolled": "yes"})
 age = ET.SubElement(name, "age", attrib={"checked": "no"})
 sex = ET.SubElement(name, "sex")
 sex.text = ''
 name2 = ET.SubElement(new_xml, "name", attrib={"enrolled": "no"})
 age = ET.SubElement(name2, "age")
 age.text = ''

 et = ET.ElementTree(new_xml)  # 生成文档对象
 et.write("test1.xml", encoding="utf-8", xml_declaration=True)

 ET.dump(new_xml)  # 打印生成的格式

3.json & pickle

 # dic='{"name":"alex"}'
 # f=open("hello","w")
 # f.write(dic)
 #
 # f_read=open("hello","r")
 # data=f_read.read()
 # print(type(data))
 # data=eval(data)
 # print(data["name"])

 import json

 # dic={'name':'alex'}#---->{"name":"alex"}----->'{"name":"alex"}'
 # i=8                 #---->'8'
 # s='hello'          #---->"hello"------>'"hello"'
 # l=[11,22]           #---->"[11,22]"
 # #
 # f=open("new_hello","w")
 #
 # dic_str=json.dumps(dic)
 # f.write(dic_str)    #json.dump(dic,f)

 # f_read=open("new_hello","r")
 # data=json.loads(f_read.read())      # data=json.load(f)
 #
 # #
 # print(data["name"])
 # print(data)
 # print(type(data))

 # print(s)
 # print(type(s))

 # data=json.dumps(dic)

 # print(data)     #{"name": "alex"}
 # print(type(data))

 #注意：
 # import json
 #
 # with open("hello","r") as f:
 #     data=f.read()
 #     data=json.loads(data)
 #     print(data["name"])

 #----------------------pickle-------
 # import pickle

 # dic = {'name': 'alvin', 'age': 23, 'sex': 'male'}

 # print(type(dic))  # <class 'dict'>
 #
 # j = pickle.dumps(dic)
 # print(type(j))  # <class 'bytes'>
 #
 # f = open('../day22/序列化对象_pickle', 'wb')  # 注意是w是写入str,wb是写入bytes,j是'bytes'
 # f.write(j)  # -------------------等价于pickle.dump(dic,f)
 #
 # f.close()
 # # -------------------------反序列化
 # import pickle
 #
 # f = open('../day22/序列化对象_pickle', 'rb')
 # #
 # data = pickle.loads(f.read())  # 等价于data=pickle.load(f)
 #
 # print(data['age'])
 # # -------------------------shelve模块---------
 import shelve
 #
 f = shelve.open(r'shelve1.bak')  # 目的：将一个字典放入文本 f={}
 #
 f['stu1_info']={'name':'alex','age':''}
 f['stu2_info']={'name':'alvin','age':''}
 f['school_info']={'website':'oldboyedu.com','city':'beijing'}
 f.close()

 print(f.get('stu1_info')['age'])

 # dic={}
 #
 # dic["name"]="alvin"
 # dic["info"]={"name":"alex"}

4.eval

 print(eval("12+(34*6+2-5*(2-1))"))

5.sys

 import sys
 # # print(sys.argv)
 #
 # command=sys.argv[1]
 # path=sys.argv[2]
 #
 # if command=="post":
 #     pass
 #
 # elif command=="get":
 #     pass
 #
 import time
 for i in range(100):
     sys.stdout.write("#")
     time.sleep(0.1)
     sys.stdout.flush()