datetime shutil xml collections模块

# datetime模块

import datetime
now_time = datetime.datetime.now()
print(now_time)

# 只能调整的字段：weeks days hours minutes seconds
# print(datetime.datetime.now() + datetime.timedelta(weeks=3)) # 三周后
# print(datetime.datetime.now() + datetime.timedelta(weeks=-3)) # 三周前
# print(datetime.datetime.now() + datetime.timedelta(days=-3)) # 三天前
# print(datetime.datetime.now() + datetime.timedelta(days=3)) # 三天后
# print(datetime.datetime.now() + datetime.timedelta(hours=5)) # 5小时后
# print(datetime.datetime.now() + datetime.timedelta(hours=-5)) # 5小时前
# print(datetime.datetime.now() + datetime.timedelta(minutes=-15)) # 15分钟前
# print(datetime.datetime.now() + datetime.timedelta(minutes=15)) # 15分钟后
# print(datetime.datetime.now() + datetime.timedelta(seconds=-70)) # 70秒前
# print(datetime.datetime.now() + datetime.timedelta(seconds=70)) # 70秒后

current_time = datetime.datetime.now() # 现在时间
# 可直接调整到指定的 年 月 日 时 分 秒 等

print(current_time.replace(year=1977))  # 直接调整到1977年
print(current_time.replace(month=1))  # 直接调整到1月份
print(current_time.replace(year=1989,month=4,day=25))  # 1989-04-25 18:49:05.898601

# 将时间戳转化成时间
print(datetime.date.fromtimestamp(1232132131))  # 2009-01-17

# shutil模块

import shutil
shutil.copyfileobj(open('shutil1', encoding='utf-8'), open('shutil2',encoding='utf-8', mode='w')) #以写的模式复制到空的shutil2文件
shutil.copyfile('a1.log','abc.txt')  # 复制一个a1.log变成abc.txt，相当于复制粘贴   copy文件 -->复制重命名一个文件

import shutil
import time
ret = shutil.make_archive("blog_bak%s" %(time.strftime('%Y-%m-%d')), 'gztar', root_dir='blog') # 打包blog文件夹变成blog_bak+日期.tar.gz

import tarfile
t= tarfile.open(r'D:pythonpython练习day8log_bak2018-12-05.tar.gz','r')  #解包
t.extractall('blog2')   #解包到当前目录下变成blog2
t.close()　

# xml（了解）

<?xml version="1.0"?>
<data>
    <country name="Liechtenstein">
        <rank updated="yes">2</rank>
        <year name="脸哥">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 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>
<

# import xml.etree.ElementTree as ET
# tree = ET.parse('二狗.xml')
# root = tree.getroot()
# print(root)  # <Element 'data' at 0x000000000274D548>
# print([tag for tag in root])

# 查
# print(root.iter('year'))  # 查询所有的year标签。
# for i in root.iter('year'):
#     print(i)

#
# print(root.find('country')) # 找到第一个就返回


# print(root.findall('country'))  # 找到子标签所有的country

# 找寻标签属性以及内容
#
# year_list = [year for year in root.iter('year')]
# print(year_list[0].attrib) #{name:'脸哥'}

# print(year_list[0].text)

# collections 模块  #用在坐标，矢量 半径表示一个圆

from collections import namedtuple
Point = namedtuple('Point', ['x', 'y'])
p = Point(1, 2)
# print(p[0])
print(p.x)

　

deque

使用list存储数据时，按索引访问元素很快，但是插入和删除元素就很慢了，因为list是线性存储，数据量大的时候，插入和删除效率很低。

deque是为了高效实现插入和删除操作的双向列表，适合用于队列和栈：

from collections import deque
# q = deque(['a','b','c'])
q = deque(['a', 'b', 'c'])
q.append('前')
q.append('后')
print(q)   #deque(['a', 'b', 'c', '前', '后'])