1 sys.argv           命令行参数List，第一个元素是程序本身路径
2 sys.exit(n)        退出程序，正常退出时exit(0)
3 sys.version        获取Python解释程序的版本信息
4 sys.maxint         最大的Int值
5 sys.path           返回模块的搜索路径，初始化时使用PYTHONPATH环境变量的值
6 sys.platform       返回操作系统平台名称
7 sys.stdin          输入相关
8 sys.stdout         输出相关
9 sys.stderror       错误相关

$ Python --version
Python 2.7.6

 1 $ Python --help
 2 usage: Python [option] ... [-c cmd | -m mod | file | -] [arg] ...
 3 Options and arguments (and corresponding environment variables):
 4 -B     : don‘t write .py[co] files on import; also PYTHONDONTWRITEBYTECODE=x
 5 -c cmd : program passed in as string (terminates option list)
 6 -d     : debug output from parser; also PYTHONDEBUG=x
 7 -E     : ignore PYTHON* environment variables (such as PYTHONPATH)
 8 -h     : print this help message and exit (also --help)
 9 -i     : inspect interactively after running script; forces a prompt even
10          if stdin does not appear to be a terminal; also PYTHONINSPECT=x
11 -m mod : run library module as a script (terminates option list)
12 -O     : optimize generated bytecode slightly; also PYTHONOPTIMIZE=x
13 -OO    : remove doc-strings in addition to the -O optimizations
14 -R     : use a pseudo-random salt to make hash() values of various types be
15          unpredictable between separate invocations of the interpreter, as
16          a defense against denial-of-service attacks

1 if __name__==‘__main__‘:
2     test()

1 >>> import sys 2 >>> sys.path 3 [‘‘, ‘/usr/local/lib/python3.5/dist-packages/setuptools-18.1-py3.5.egg‘, ‘/usr/local/lib/python3.5/dist-packages/pip-7.1.0-py3.5.egg‘, ‘/usr/lib/python35.zip‘, ‘/usr/lib/python3.5‘, ‘/usr/lib/python3.5/plat-x86_64-linux-gnu‘, ‘/usr/lib/python3.5/lib-dynload‘, ‘/usr/local/lib/python3.5/dist-packages‘, ‘/usr/lib/python3/dist-packages‘]

 1 os.getcwd()                 获取当前工作目录，即当前python脚本工作的目录路径
 2 os.chdir("dirname")         改变当前脚本工作目录；相当于shell下cd
 3 os.curdir                   返回当前目录: (‘.‘)
 4 os.pardir                   获取当前目录的父目录字符串名：(‘..‘)
 5 os.makedirs(‘dir1/dir2‘)    可生成多层递归目录
 6 os.removedirs(‘dirname1‘)   若目录为空，则删除，并递归到上一级目录，如若也为空，则删除，依此类推
 7 os.mkdir(‘dirname‘)         生成单级目录；相当于shell中mkdir dirname
 8 os.rmdir(‘dirname‘)         删除单级空目录，若目录不为空则无法删除，报错；相当于shell中rmdir dirname
 9 os.listdir(‘dirname‘)       列出指定目录下的所有文件和子目录，包括隐藏文件，并以列表方式打印
10 os.remove()                 删除一个文件
11 os.rename("oldname","new")  重命名文件/目录
12 os.stat(‘path/filename‘)    获取文件/目录信息
13 os.sep                      操作系统特定的路径分隔符，win下为"\\",Linux下为"/"
14 os.linesep                  当前平台使用的行终止符，win下为"\t\n",Linux下为"\n"
15 os.pathsep                  用于分割文件路径的字符串
16 os.name                     字符串指示当前使用平台。win->‘nt‘; Linux->‘posix‘
17 os.system("bash command")   运行shell命令，直接显示
18 os.environ                  获取系统环境变量
19 os.path.abspath(path)       返回path规范化的绝对路径
20 os.path.split(path)         将path分割成目录和文件名二元组返回
21 os.path.dirname(path)       返回path的目录。其实就是os.path.split(path)的第一个元素
22 os.path.basename(path)      返回path最后的文件名。如何path以／或\结尾，那么就会返回空值。即os.path.split(path)的第二个元素
23 os.path.exists(path)        如果path存在，返回True；如果path不存在，返回False
24 os.path.isabs(path)         如果path是绝对路径，返回True
25 os.path.isfile(path)        如果path是一个存在的文件，返回True。否则返回False
26 os.path.isdir(path)         如果path是一个存在的目录，则返回True。否则返回False
27 os.path.join(path1[, path2[, ...]])  将多个路径组合后返回，第一个绝对路径之前的参数将被忽略
28 os.path.getatime(path)      返回path所指向的文件或者目录的最后存取时间
29 os.path.getmtime(path)      返回path所指向的文件或者目录的最后修改时间

 1 import hashlib
 2  
 3 # ######## md5 ########
 4 hash = hashlib.md5()
 5 # help(hash.update)
 6 hash.update(‘admin‘)
 7 print(hash.hexdigest())

    21232f297a57a5a743894a0e4a801fc3

 1 zh@zh-Lenovo-G470 ~ $ python  #进入环境
 2 Python 2.7.12 (default, Nov 19 2016, 06:48:10) 
 3 [GCC 5.4.0 20160609] on linux2
 4 Type "help", "copyright", "credits" or "license" for more information.
 5 >>> import hashlib  #导入模块
 6 >>> hash = hashlib.md5() #加密方法
 7 >>> hash.update("Hello") #加密的字符串
 8 >>> hash.update("It‘s me")
 9 >>> hash.digest() #以二进制格式
10 ‘]\xde\xb4{/\x92Z\xd0\xbf$\x9cR\xe3Br\x8a‘
11 >>> hash.hexdigest() #十六进制
12 ‘5ddeb47b2f925ad0bf249c52e342728a‘
13 >>> 

10  
11 ######## sha1 ########
12  
13 hash = hashlib.sha1()
14 hash.update(‘admin‘)
15 print(hash.hexdigest())
16 
结果：d033e22ae348aeb5660fc2140aec35850c4da997 

17 # ######## sha256 ########
18  
19 hash = hashlib.sha256()
20 hash.update(‘admin‘)
21 print(hash.hexdigest())
22  
23 结果：8c6976e5b5410415bde908bd4dee15dfb167a9c873fc4bb8a81f6f2ab448a918

 
24 # ######## sha384 ########
25  
26 hash = hashlib.sha384()
27 hash.update(‘admin‘)
28 print(hash.hexdigest())
29 
结果：9ca694a90285c034432c9550421b7b9dbd5c0f4b6673f05f6dbce58052ba20e4248041956ee8c9a2ec9f10290cdc0782
 
30 # ######## sha512 ########
31  
32 hash = hashlib.sha512()
33 hash.update(‘admin‘)
34 print(hash.hexdigest())

结果：c7ad44cbad762a5da0a452f9e854fdc1e0e7a52a38015f23f3eab1d80b931dd472634dfac71cd34ebc35d16ab7fb8a90c81f975113d6c7538dc69dd8de9077ec

1 import random
2  
3 print(random.random())
4 print(random.randint(1, 2))
5 print(random.randrange(1, 10))

结果：注意每一运行结果在范围内随机

  0.265829883567
  2
  6

次数
 1 ‘.‘     默认匹配除\n之外的任意一个字符，若指定flag DOTALL,则匹配任意字符，包括换行
 2 ‘^‘     匹配字符开头，若指定flags MULTILINE,这种也可以匹配上(r"^a","\nabc\neee",flags=re.MULTILINE)
 3 ‘$‘     匹配字符结尾，或e.search("foo$","bfoo\nsdfsf",flags=re.MULTILINE).group()也可以
 4 ‘*‘     匹配*号前的字符0次或多次，re.findall("ab*","cabb3abcbbac")  结果为[‘abb‘, ‘ab‘, ‘a‘]
 5 ‘+‘     匹配前一个字符1次或多次，re.findall("ab+","ab+cd+abb+bba") 结果[‘ab‘, ‘abb‘]
 6 ‘?‘     匹配前一个字符1次或0次
 7 ‘{m}‘   匹配前一个字符m次
 8 ‘{n,m}‘ 匹配前一个字符n到m次，re.findall("ab{1,3}","abb abc abbcbbb") 结果‘abb‘, ‘ab‘, ‘abb‘]
 9 ‘|‘     匹配|左或|右的字符，re.search("abc|ABC","ABCBabcCD").group() 结果‘ABC‘
10 ‘(...)‘ 分组匹配，re.search("(abc){2}a(123|456)c", "abcabca456c").group() 结果 abcabca456c
11  

字符
13 ‘\A‘    只从字符开头匹配，re.search("\Aabc","alexabc") 是匹配不到的
14 ‘\Z‘    匹配字符结尾，同$
15 ‘\d‘    匹配数字0-9
16 ‘\D‘    匹配非数字
17 ‘\w‘    匹配[A-Za-z0-9]
18 ‘\W‘    匹配非[A-Za-z0-9]
19 ‘s‘     匹配空白字符、\t、\n、\r , re.search("\s+","ab\tc1\n3").group() 结果 ‘\t‘
20  
21 ‘(?P<name>...)‘ 分组匹配 re.search("(?P<province>[0-9]{4})(?P<city>[0-9]{2})(?P<birthday>[0-9]{4})","371481199306143242").groupdict("city") 结果{‘province‘: ‘3714‘, ‘city‘: ‘81‘, ‘birthday‘: ‘1993‘}
22 　　

1 import re #导入模块名
2  
3 p = re.compile("^[0-9]")  #生成要匹配的正则对象 ， ^代表从开头匹配，[0-9]代表匹配0至9的任意一个数字， 所以这里的意思是对传进来的字符串进行匹配，如果这个字符串的开头第一个字符是数字，就代表匹配上了
4  
5 m = p.match(‘14534Abc‘)   #按上面生成的正则对象 去匹配 字符串， 如果能匹配成功，这个m就会有值， 否则m为None<br><br>if m: #不为空代表匹配上了
6 print(m.group())　　　　#m.group()返回匹配上的结果，此处为1，因为匹配上的是1这个字符<br>else:<br>　　print("doesn‘t match.")<br>

1 m = p.match("^[0-9]",‘14534Abc‘)

 1 # match，从起始位置开始匹配，匹配成功返回一个对象，未匹配成功返回None
 2  
 3  
 4  match(pattern, string, flags=0)
 5  # pattern： 正则模型
 6  # string ： 要匹配的字符串
 7  # falgs  ： 匹配模式
 8      X  VERBOSE     Ignore whitespace and comments for nicer looking RE‘s.
 9      I  IGNORECASE  Perform case-insensitive matching.
10      M  MULTILINE   "^" matches the beginning of lines (after a newline)
11                     as well as the string.
12                     "$" matches the end of lines (before a newline) as well
13                     as the end of the string.
14      S  DOTALL      "." matches any character at all, including the newline.
15  
16      A  ASCII       For string patterns, make \w, \W, \b, \B, \d, \D
17                     match the corresponding ASCII character categories
18                     (rather than the whole Unicode categories, which is the
19                     default).
20                     For bytes patterns, this flag is the only available
21                     behaviour and needn‘t be specified.
22       
23      L  LOCALE      Make \w, \W, \b, \B, dependent on the current locale.
24      U  UNICODE     For compatibility only. Ignored for string patterns (it
25                     is the default), and forbidden for bytes patterns.

1 # search,浏览整个字符串去匹配第一个，匹配整个字符串，直到找到一个匹配，未匹配成功返回None
2 # search(pattern, string, flags=0)

1 # findall，找到所有要匹配的字符并返回列表格式
获取非重复的匹配列表；如果有一个组则以列表形式返回，且每一个匹配均是字符串；如果模型中有多个组，则以列表形式返回，且每一个匹配均是元祖；
2 # 空的匹配也会包含在结果中
3 #findall(pattern, string, flags=0)

1 >>>m = re.findall("[0-9]", "alex1rain2jack3helen rachel8")
2 >>>print(m)<br>
3 输出：[‘1‘, ‘2‘, ‘3‘, ‘8‘]

1 # sub，替换匹配成功的指定位置字符串
2  
3 sub(pattern, repl, string, count=0, flags=0)
4 # pattern： 正则模型
5 # repl   ： 要替换的字符串或可执行对象
6 # string ： 要匹配的字符串
7 # count  ： 指定匹配个数
8 # flags  ： 匹配模式

1 m=re.sub("[0-9]","|", "alex1rain2jack3helen rachel8",count=2 )
2 print(m)
3 输出：alex|rain|jack3helen rachel8　　

1 # split， 将匹配到的格式当做分割点对字符串分割成列表
2  
3 split(pattern, string, maxsplit=0, flags=0)
4 # pattern： 正则模型
5 # string ： 要匹配的字符串
6 # maxsplit：指定分割个数
7 # flags  ： 匹配模式

1 >>>m = re.split("[0-9]", "alex1rain2jack3helen rachel8")
2 >>>print(m)
3 输出：　[‘alex‘, ‘rain‘, ‘jack‘, ‘helen rachel‘, ‘‘]

 1 # 注释1
 2 ;  注释2
 3  
 4 [section1] # 节点
 5 k1 = v1    # 值
 6 k2:v2       # 值
 7  
 8 [section2] # 节点
 9 k1 = v1    # 值
10 
11 指定格式

 1 [DEFAULT] # 节点          #全局写在每个section下面，下面读时从循环能看出来
 2 ServerAliveInterval = 45  
 3 Compression = yes 

 4 CompressionLevel = 9  
 5 ForwardX11 = yes  
 6 
 7 [bitbucket.org] 
 8 User = hg  
 9 

 10 [topsecret.server.com]
 11 Port = 50022 
 12 ForwardX11 = no

 1 import configparser
 2  
 3 config = configparser.ConfigParser()
 4 config["DEFAULT"] = {‘ServerAliveInterval‘: ‘45‘,
 5                       ‘Compression‘: ‘yes‘,
 6                      ‘CompressionLevel‘: ‘9‘}
 7  
 8 config[‘bitbucket.org‘] = {}
 9 config[‘bitbucket.org‘][‘User‘] = ‘hg‘
10 config[‘topsecret.server.com‘] = {}
11 topsecret = config[‘topsecret.server.com‘]
12 topsecret[‘Host Port‘] = ‘50022‘     # mutates the parser
13 topsecret[‘ForwardX11‘] = ‘no‘  # same here
14 config[‘DEFAULT‘][‘ForwardX11‘] = ‘yes‘
15 with open(‘example.ini‘, ‘w‘) as configfile:
16    config.write(configfile)

 1 # coding=utf-8
 2 import ConfigParser
 3 
 4 config = ConfigParser.ConfigParser()
 5 config.read(‘example.ini‘)
 6 
 7 # ########## 读 ##########
 8 # secs = config.sections() #获取所有节点
 9 # print (secs)
10 # options = config.options(‘bitbucket.org‘)#获取指定节点下所有的建
11 # print (options)
12 ‘‘‘
13 结果:
14 /usr/bin/python2.7 /home/zh/PycharmProjects/s12/day1/b.py
15 [‘bitbucket.org‘, ‘topsecret.server.com‘]
16 [‘user‘, ‘compression‘, ‘serveraliveinterval‘, ‘compressionlevel‘, ‘forwardx11‘]
17 
18 Process finished with exit code 0
19 
20 ‘‘‘
21 
22 # item_list = config.items(‘bitbucket.org‘)#获取指定节点下所有的键值对
23 # print item_list
24 ‘‘‘
25 结果:
26 [(‘compression‘, ‘yes‘), (‘serveraliveinterval‘, ‘45‘), (‘compressionlevel‘, ‘9‘), (‘forwardx11‘, ‘yes‘), (‘user‘, ‘hg‘)]
27 
28 ‘‘‘
29 
30 #val = config.get(‘bitbucket.org‘,‘forwardx11‘) #获取指定节点下指定key的值
31 # val = config.getboolean(‘bitbucket.org‘,‘forwardx11‘)
32 # print (val)
33 ‘‘‘
34 结果:
35 [(‘compression‘, ‘yes‘), (‘serveraliveinterval‘, ‘45‘), (‘compressionlevel‘, ‘9‘), (‘forwardx11‘, ‘yes‘), (‘user‘, ‘hg‘)]
36 True
37 
38 ‘‘‘

 1 <?xml version="1.0"?>
 2 <data> #xml的根节点可随便起名
 3     <country name="Liechtenstein"> #子节点，相当于json里面的k，其实都是字典套字典，xml占用空间比json大
 4         <rank updated="yes">2</rank> #节点属性和值
 5         <year>2008</year>
 6         <gdppc>141100</gdppc>
 7         <neighbor name="Austria" direction="E"/>
 8         <neighbor name="Switzerland" direction="W"/>
 9     </country>
10     <country name="Singapore"> #注意，这里和上面的不一样多，因为都是可以自定义的，多少都行
11         <rank updated="yes">5</rank>
12         <year>2011</year>
13         <gdppc>59900</gdppc>
14         <neighbor name="Malaysia" direction="N"/>
15     </country>
16     <country name="Panama">
17         <rank updated="yes">69</rank>
18         <year>2011</year>
19         <gdppc>13600</gdppc>
20         <neighbor name="Costa Rica" direction="W"/>
21         <neighbor name="Colombia" direction="E"/>
22     </country>
23 </data>

 1 # coding=utf-8
 2 import xml.etree.ElementTree as ET
 3 
 4 tree = ET.parse("test.xml") # 直接解析xml文件
 5 root = tree.getroot() # 获取xml文件的根节点
 6 print(root.tag)
 7 
 8 # 遍历xml文档
 9 for child in root:
10     print(child.tag, child.attrib)
11     for i in child:
12         print(i.tag, i.text)
13 
14 # 只遍历year 节点
15 for node in root.iter(‘year‘):
16     print(node.tag, node.text)

 1 data
 2 country {‘name‘: ‘Liechtenstein‘}
 3 rank 2
 4 year 2008
 5 gdppc 141100
 6 neighbor None
 7 neighbor None
 8 country {‘name‘: ‘Singapore‘}
 9 rank 5
10 year 2011
11 gdppc 59900
12 neighbor None
13 country {‘name‘: ‘Panama‘}
14 rank 69
15 year 2011
16 gdppc 13600
17 neighbor None
18 neighbor None
19 year 2008
20 year 2011
21 year 2011

 1 import xml.etree.ElementTree as ET
 2  
 3 tree = ET.parse("xmltest.xml")
 4 root = tree.getroot()
 5  
 6 #修改
 7 for node in root.iter(‘year‘):
 8     new_year = int(node.text) + 1
 9     node.text = str(new_year)
10     node.set("updated","yes")
11  
12 tree.write("xmltest.xml")
13  
14  
15 #删除node
16 for country in root.findall(‘country‘):
17    rank = int(country.find(‘rank‘).text)
18    if rank > 50:
19      root.remove(country)
20  
21 tree.write(‘output.xml‘)

 1 import xml.etree.ElementTree as ET
 2  
 3  
 4 new_xml = ET.Element("namelist")
 5 name = ET.SubElement(new_xml,"name",attrib={"enrolled":"yes"})
 6 age = ET.SubElement(name,"age",attrib={"checked":"no"})
 7 sex = ET.SubElement(name,"sex")
 8 sex.text = ‘33‘
 9 name2 = ET.SubElement(new_xml,"name",attrib={"enrolled":"no"})
10 age = ET.SubElement(name2,"age")
11 age.text = ‘19‘
12  
13 et = ET.ElementTree(new_xml) #生成文档对象
14 et.write("test.xml", encoding="utf-8",xml_declaration=True)
15  
16 ET.dump(new_xml) #打印生成的格式

pip3 install requests

 1 try:
 2     arr = [1,2,3]
 3     a = arr[8]
 4 except ZeroDivisionError as e:
 5     print  e
 6 
 7 #断言
 8 def foo(s):
 9     n = int(s)
10     assert n != 0
11     return 10 / n
12 
13 def main():
14     print foo(‘0‘)
15 
16 main()

 1 import logging
 2   
 3   
 4 logging.basicConfig(filename=‘log.log‘,  #文件名
 5         #基本配置     format=‘%(asctime)s - %(name)s - %(levelname)s -%(module)s:  %(message)s‘, #格式
 6                     datefmt=‘%Y-%m-%d %H:%M:%S %p‘,
 7                     level=10)
 8   
 9 logging.debug(‘debug‘)
10 logging.info(‘info‘)
11 logging.warning(‘warning‘)
12 logging.error(‘error‘)
13 logging.critical(‘critical‘)
14 logging.log(10,‘log‘) 

1 import logging
2  
3 logging.basicConfig(filename=‘example.log‘,level=logging.INFO)
4 logging.debug(‘This message should go to the log file‘)
5 logging.info(‘So should this‘)
6 logging.warning(‘And this, too‘)

1 import logging
2 logging.basicConfig(format=‘%(asctime)s %(message)s‘, datefmt=‘%m/%d/%Y %I:%M:%S %p‘)
3 logging.warning(‘is when this event was logged.‘)

 1 import commands
 2 testmodel = commands.getoutput(‘fdisk -l ‘)   #获取用户的输出结果（结果以字符串存储）
 3 print type(testmodel)
结果：<type ‘str‘>

 4 f=commands.getstatus(‘/etc/passwd‘) #判断文件是否存在，存在返回不存在报错

 5 print f

结果：

  -rw-r--r-- 1 root root 2351 11月 19 16:02 /etc/passwd

 6 d=commands.getstatus(‘/etc/passwdsd‘)  

 7 print d

结果：

  ls: cannot access ‘/etc/passwdsd‘: No such file or directory

 8 
 9 result = commands.getstatusoutput(‘cmd‘) #获取用户的输出结果和状态正确状态为：0

 10 print result

结果：

  (32512, ‘sh: 1: cmd: not found‘)

1 import subprocess
2 subprocess.call(["ls",‘-l‘,‘/etc/‘],shell=False)  #使用python执行shell命令shell=False
3 #subprocess.call(‘ls -l /etc/ ’,shell=True)  #使用原生的shell执行命令shell=True
4 #一般建议统一使用python执行shell命名除非python没有的，在建议使用shell原生执行

结果：

  total 1288
  drwxr-xr-x 3 root root 4096 6月 28 20:39 acpi
  -rw-r--r-- 1 root root 3028 6月 28 20:00 adduser.conf

  等等等等

 1 import subprocess
 2 
 3 >>>subprocess.call(["ls",‘-l‘,‘/etc/‘],shell=False)   #执行成功返回状态码0
 4 >>>subprocess.call(["ls",‘-l‘,‘/etc/sdfsdf‘],shell=False) #执行错误直接报异常
 5 
 6 >>> subprocess.check_call(‘exit 1‘ ,shell=True)
 7 Traceback (most recent call last):
 8   File "<stdin>", line 1, in <module>
 9   File "/usr/lib/python2.7/subprocess.py", line 540, in check_call
10     raise CalledProcessError(retcode, cmd)
11 subprocess.CalledProcessError: Command ‘exit 1‘ returned non-zero exit status 1
12 >>> subprocess.check_call(‘exit 0‘ ,shell=True)
13 >>>

 1 >>> subprocess.check_output(["echo", "Hello World!"]) #执行结果成功状态码是0直接返回结果
 2 ‘Hello World!\n‘
 3 >>> subprocess.check_output(["echo1", "Hello World!"]) #执行结果失败状态码不为0直接报错
 4 Traceback (most recent call last):
 5   File "<stdin>", line 1, in <module>
 6   File "/usr/lib/python2.7/subprocess.py", line 566, in check_output
 7     process = Popen(stdout=PIPE, *popenargs, **kwargs)
 8   File "/usr/lib/python2.7/subprocess.py", line 710, in __init__
 9     errread, errwrite)
10   File "/usr/lib/python2.7/subprocess.py", line 1327, in _execute_child
11     raise child_exception
12 OSError: [Errno 2] No such file or directory

14、paramiko

1 pycrypto，由于 paramiko 模块内部依赖pycrypto，所以先下载安装pycrypto
2 pip3 install pycrypto
3 pip3 install paramiko

 1 print time.time()
 2 print time.mktime(time.localtime())
 3    
 4 print time.gmtime()    #可加时间戳参数
 5 print time.localtime() #可加时间戳参数
 6 print time.strptime(‘2014-11-11‘, ‘%Y-%m-%d‘)
 7    
 8 print time.strftime(‘%Y-%m-%d‘) #默认当前时间
 9 print time.strftime(‘%Y-%m-%d‘,time.localtime()) #默认当前时间
10 print time.asctime()
11 print time.asctime(time.localtime())
12 print time.ctime(time.time())
13    
14 import datetime
15 ‘‘‘
16 datetime.date：表示日期的类。常用的属性有year, month, day
17 datetime.time：表示时间的类。常用的属性有hour, minute, second, microsecond
18 datetime.datetime：表示日期时间
19 datetime.timedelta：表示时间间隔，即两个时间点之间的长度
20 timedelta([days[, seconds[, microseconds[, milliseconds[, minutes[, hours[, weeks]]]]]]])
21 strftime("%Y-%m-%d")
22 ‘‘‘
23 import datetime
24 print datetime.datetime.now()
25 print datetime.datetime.now() - datetime.timedelta(days=5)