python之shelve、xml、configparser模块

时间：2023-03-09 01:20:12
python之shelve、xml、configparser模块

一、shelve模块

 shelve模块比pickle模块简单，只有一个open函数，返回类似字典的对象，可读可写;key必须为字符串，而值可以是python所支持的数据类型
import shelve

f=shelve.open(r'sheve.txt')

# f['stu1_info']={'name':'egon','age':18,'hobby':['piao','smoking','drinking']}

# f['stu2_info']={'name':'gangdan','age':53}

# f['school_info']={'website':'http://www.pypy.org','city':'beijing'}

print(f['stu1_info']['hobby'])

f.close()

二、xml模块

xml是实现不同语言或程序之间进行数据交换的协议，跟json差不多，但json使用起来更简单，不过，古时候，在json还没诞生的黑暗年代，大家只能选择用xml呀，至今很多传统公司如金融行业的很多系统的接口还主要是xml。
xml的格式如下，就是通过<>节点来区别数据结构的:

<?xml version="1.0"?>

<data>

    <country name="Liechtenstein">

        <rank updated="yes">2</rank>

        <year>2008</year>

        <gdppc>141100</gdppc>

        <neighbor name="Austria" direction="E"/>

        <neighbor name="Switzerland" direction="W"/>

    </country>

    <country name="Singapore">

        <rank updated="yes">5</rank>

        <year>2011</year>

        <gdppc>59900</gdppc>

        <neighbor name="Malaysia" direction="N"/>

    </country>

    <country name="Panama">

        <rank updated="yes">69</rank>

        <year>2011</year>

        <gdppc>13600</gdppc>

        <neighbor name="Costa Rica" direction="W"/>

        <neighbor name="Colombia" direction="E"/>

    </country>

</data>
xml协议在各个语言里的都 是支持的，在python中可以用以下模块操作xml：

# print(root.iter('year')) #全文搜索

# print(root.find('country')) #在root的子节点找，只找一个

# print(root.findall('country')) #在root的子节点找，找所有
import xml.etree.ElementTree as ET

tree = ET.parse("xmltest.xml")

root = tree.getroot()

print(root.tag)

#遍历xml文档

for child in root:

    print('========>',child.tag,child.attrib,child.attrib['name'])

    for i in child:

        print(i.tag,i.attrib,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("xmltest.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','yes')

    node.set('version','1.0')

tree.write('test.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')
#在country内添加（append）节点year2

import xml.etree.ElementTree as ET

tree = ET.parse("a.xml")

root=tree.getroot()

for country in root.findall('country'):

    for year in country.findall('year'):

        if int(year.text) > 2000:

            year2=ET.Element('year2')

            year2.text='新年'

            year2.attrib={'update':'yes'}

            country.append(year2) #往country节点下添加子节点

tree.write('a.xml.swap')
自己创建xml文档：

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 = '33'

name2 = ET.SubElement(new_xml,"name",attrib={"enrolled":"no"})

age = ET.SubElement(name2,"age")

age.text = '19'

et = ET.ElementTree(new_xml) #生成文档对象

et.write("test.xml", encoding="utf-8",xml_declaration=True)

ET.dump(new_xml) #打印生成的格式

三、configparser模块

配置文件如下：

复制代码

# 注释1

; 注释2

[section1]

k1 = v1

k2:v2

user=egon

age=18

is_admin=true

salary=31

[section2]

k1 = v1
读取:

import configparser

config=configparser.ConfigParser()

config.read('a.cfg')

#查看所有的标题

res=config.sections() #['section1', 'section2']

print(res)

#查看标题section1下所有key=value的key

options=config.options('section1')

print(options) #['k1', 'k2', 'user', 'age', 'is_admin', 'salary']

#查看标题section1下所有key=value的(key,value)格式

item_list=config.items('section1')

print(item_list) #[('k1', 'v1'), ('k2', 'v2'), ('user', 'egon'), ('age', '18'), ('is_admin', 'true'), ('salary', '31')]

#查看标题section1下user的值=>字符串格式

val=config.get('section1','user')

print(val) #egon

#查看标题section1下age的值=>整数格式

val1=config.getint('section1','age')

print(val1) #18

#查看标题section1下is_admin的值=>布尔值格式

val2=config.getboolean('section1','is_admin')

print(val2) #True

#查看标题section1下salary的值=>浮点型格式

val3=config.getfloat('section1','salary')

print(val3) #31.0
改写:

import configparser

config=configparser.ConfigParser()

config.read('a.cfg',encoding='utf-8')

#删除整个标题section2

config.remove_section('section2')

#删除标题section1下的某个k1和k2

config.remove_option('section1','k1')

config.remove_option('section1','k2')

#判断是否存在某个标题

print(config.has_section('section1'))

#判断标题section1下是否有user

print(config.has_option('section1',''))

#添加一个标题

config.add_section('egon')

#在标题egon下添加name=egon,age=18的配置

config.set('egon','name','egon')

config.set('egon','age',18) #报错,必须是字符串

#最后将修改的内容写入文件,完成最终的修改

config.write(open('a.cfg','w'))


import configparser

config = configparser.ConfigParser()

config["DEFAULT"] = {'ServerAliveInterval': '45',

                      'Compression': 'yes',

                     'CompressionLevel': '9'}

config['bitbucket.org'] = {}

config['bitbucket.org']['User'] = 'hg'

config['topsecret.server.com'] = {}

topsecret = config['topsecret.server.com']

topsecret['Host Port'] = '50022'     # mutates the parser

topsecret['ForwardX11'] = 'no'  # same here

config['DEFAULT']['ForwardX11'] = 'yes'

with open('example.ini', 'w') as configfile:

   config.write(configfile)

基于上述方法添加一个ini文档

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