模块介绍
time &datetime模块
random
os
sys
shutil
json & picle
shelve
xml处理
yaml处理
configparser
hashlib
subprocess
logging模块
re正则表达式
模块用一砣代码实现了某个功能的代码集合。
类似于函数式编程和面向过程编程函数式编程则完成一个功能其他代码用来调用即可提供了代码的重用性和代码间的耦合。而对于一个复杂的功能来可能需要多个函数才能完成函数又可以在不同的.py文件中n个 .py 文件组成的代码集合就称为模块。
如os 是系统相关的模块file是文件操作相关的模块
模块分为三种
自定义模块
内置标准模块又称标准库
开源模块
自定义模块 和开源模块的使用参考 http://www.cnblogs.com/wupeiqi/articles/4963027.html
time & datetime模块
1 #_*_coding:utf-8_*_
2 __author__ = 'Alex Li'
3
4 import time
5
6
7 # print(time.clock()) #返回处理器时间,3.3开始已废弃 , 改成了time.process_time()测量处理器运算时间,不包括sleep时间,不稳定,mac上测不出来
8 # print(time.altzone) #返回与utc时间的时间差,以秒计算\
9 # print(time.asctime()) #返回时间格式"Fri Aug 19 11:14:16 2016",
10 # print(time.localtime()) #返回本地时间 的struct time对象格式
11 # print(time.gmtime(time.time()-800000)) #返回utc时间的struc时间对象格式
12
13 # print(time.asctime(time.localtime())) #返回时间格式"Fri Aug 19 11:14:16 2016",
14 #print(time.ctime()) #返回Fri Aug 19 12:38:29 2016 格式, 同上
15
16
17
18 # 日期字符串 转成 时间戳
19 # string_2_struct = time.strptime("2016/05/22","%Y/%m/%d") #将 日期字符串 转成 struct时间对象格式
20 # print(string_2_struct)
21 # #
22 # struct_2_stamp = time.mktime(string_2_struct) #将struct时间对象转成时间戳
23 # print(struct_2_stamp)
24
25
26
27 #将时间戳转为字符串格式
28 # print(time.gmtime(time.time()-86640)) #将utc时间戳转换成struct_time格式
29 # print(time.strftime("%Y-%m-%d %H:%M:%S",time.gmtime()) ) #将utc struct_time格式转成指定的字符串格式
30
31
32
33
34
35 #时间加减
36 import datetime
37
38 # print(datetime.datetime.now()) #返回 2016-08-19 12:47:03.941925
39 #print(datetime.date.fromtimestamp(time.time()) ) # 时间戳直接转成日期格式 2016-08-19
40 # print(datetime.datetime.now() )
41 # print(datetime.datetime.now() + datetime.timedelta(3)) #当前时间+3天
42 # print(datetime.datetime.now() + datetime.timedelta(-3)) #当前时间-3天
43 # print(datetime.datetime.now() + datetime.timedelta(hours=3)) #当前时间+3小时
44 # print(datetime.datetime.now() + datetime.timedelta(minutes=30)) #当前时间+30分
45
46
47 #
48 # c_time = datetime.datetime.now()
49 # print(c_time.replace(minute=3,hour=2)) #时间替换
| Directive | Meaning | Notes |
|---|---|---|
%a |
Locale’s abbreviated weekday name. | |
%A |
Locale’s full weekday name. | |
%b |
Locale’s abbreviated month name. | |
%B |
Locale’s full month name. | |
%c |
Locale’s appropriate date and time representation. | |
%d |
Day of the month as a decimal number [01,31]. | |
%H |
Hour (24-hour clock) as a decimal number [00,23]. | |
%I |
Hour (12-hour clock) as a decimal number [01,12]. | |
%j |
Day of the year as a decimal number [001,366]. | |
%m |
Month as a decimal number [01,12]. | |
%M |
Minute as a decimal number [00,59]. | |
%p |
Locale’s equivalent of either AM or PM. | (1) |
%S |
Second as a decimal number [00,61]. | (2) |
%U |
Week number of the year (Sunday as the first day of the week) as a decimal number [00,53]. All days in a new year preceding the first Sunday are considered to be in week 0. | (3) |
%w |
Weekday as a decimal number [0(Sunday),6]. | |
%W |
Week number of the year (Monday as the first day of the week) as a decimal number [00,53]. All days in a new year preceding the first Monday are considered to be in week 0. | (3) |
%x |
Locale’s appropriate date representation. | |
%X |
Locale’s appropriate time representation. | |
%y |
Year without century as a decimal number [00,99]. | |
%Y |
Year with century as a decimal number. | |
%z |
Time zone offset indicating a positive or negative time difference from UTC/GMT of the form +HHMM or -HHMM, where H represents decimal hour digits and M represents decimal minute digits [-23:59, +23:59]. | |
%Z |
Time zone name (no characters if no time zone exists). | |
%% |
A literal '%' character. |
random模块
随机数
mport randomprint random.random()print random.randint(1,2)print random.randrange(1,10)
生成随机验证码
import randomcheckcode = ''for i in range(4): current = random.randrange(0,4) if current != i: temp = chr(random.randint(65,90)) else: temp = random.randint(0,9) checkcode += str(temp)print checkcode
OS模块
提供对操作系统进行调用的接口
os.getcwd() 获取当前工作目录即当前python脚本工作的目录路径os.chdir("dirname") 改变当前脚本工作目录相当于shell下cdos.curdir 返回当前目录: ('.')os.pardir 获取当前目录的父目录字符串名('..')os.makedirs('dirname1/dirname2') 可生成多层递归目录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os.mkdir('dirname') 生成单级目录相当于shell中mkdir dirnameos.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 dirnameos.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os.remove() 删除一个文件os.rename("oldname","newname") 重命名文件/目录os.stat('path/filename') 获取文件/目录信息os.sep 输出操作系统特定的路径分隔符win下为"\\",Linux下为"/"os.linesep 输出当前平台使用的行终止符win下为"\t\n",Linux下为"\n"os.pathsep 输出用于分割文件路径的字符串os.name 输出字符串指示当前使用平台。win->'nt'; Linux->'posix'os.system("bash command") 运行shell命令直接显示os.environ 获取系统环境变量os.path.abspath(path) 返回path规范化的绝对路径os.path.split(path) 将path分割成目录和文件名二元组返回os.path.dirname(path) 返回path的目录。其实就是os.path.split(path)的第一个元素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os.path.exists(path) 如果path存在返回True如果path不存在返回Falseos.path.isabs(path) 如果path是绝对路径返回Trueos.path.isfile(path) 如果path是一个存在的文件返回True。否则返回Falseos.path.isdir(path) 如果path是一个存在的目录则返回True。否则返回Falseos.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os.path.getatime(path) 返回path所指向的文件或者目录的最后存取时间os.path.getmtime(path) 返回path所指向的文件或者目录的最后修改时间
更多
https://docs.python.org/2/library/os.html?highlight=os#module-os
sys模块
sys.argv 命令行参数List第一个元素是程序本身路径sys.exit(n) 退出程序正常退出时exit(0)sys.version 获取Python解释程序的版本信息sys.maxint 最大的Int值sys.path 返回模块的搜索路径初始化时使用PYTHONPATH环境变量的值sys.platform 返回操作系统平台名称sys.stdout.write('please:')val = sys.stdin.readline()[:-1]
shutil 模块
直接参考 http://www.cnblogs.com/wupeiqi/articles/4963027.html
json & pickle 模块
用于序列化的两个模块
json用于字符串 和 python数据类型间进行转换
pickle用于python特有的类型 和 python的数据类型间进行转换
Json模块提供了四个功能dumps、dump、loads、load
pickle模块提供了四个功能dumps、dump、loads、load
shelve 模块
shelve模块是一个简单的k,v将内存数据通过文件持久化的模块可以持久化任何pickle可支持的python数据格式
import shelve d = shelve.open('shelve_test') #打开一个文件 class Test(object): def __init__(self,n): self.n = n t = Test(123) t2 = Test(123334) name = ["alex","rain","test"]d["test"] = name #持久化列表d["t1"] = t #持久化类d["t2"] = t2 d.close()
xml处理模块
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
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) 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)
修改和删除xml文档内容
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") tree.write("xmltest.xml") #删除nodefor country in root.findall('country'): rank = int(country.find('rank').text) if rank > 50: root.remove(country) tree.write('output.xml')
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
PyYAML模块
Python也可以很容易的处理ymal文档格式只不过需要安装一个模块参考文档http://pyyaml.org/wiki/PyYAMLDocumentation
ConfigParser模块
用于生成和修改常见配置文档当前模块的名称在 python 3.x 版本中变更为 configparser。
来看一个好多软件的常见文档格式如下
[DEFAULT]ServerAliveInterval = 45Compression = yesCompressionLevel = 9ForwardX11 = yes [bitbucket.org]User = hg [topsecret.server.com]Port = 50022ForwardX11 = no
如果想用python生成一个这样的文档怎么做呢
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 parsertopsecret['ForwardX11'] = 'no' # same hereconfig['DEFAULT']['ForwardX11'] = 'yes'with open('example.ini', 'w') as configfile: config.write(configfile)
写完了还可以再读出来哈。
>>> import configparser>>> config = configparser.ConfigParser()>>> config.sections()[]>>> config.read('example.ini')['example.ini']>>> config.sections()['bitbucket.org', 'topsecret.server.com']>>> 'bitbucket.org' in configTrue>>> 'bytebong.com' in configFalse>>> config['bitbucket.org']['User']'hg'>>> config['DEFAULT']['Compression']'yes'>>> topsecret = config['topsecret.server.com']>>> topsecret['ForwardX11']'no'>>> topsecret['Port']'50022'>>> for key in config['bitbucket.org']: print(key)...usercompressionlevelserveraliveintervalcompressionforwardx11>>> config['bitbucket.org']['ForwardX11']'yes'
configparser增删改查语法
[section1]k1 = v1k2:v2 [section2]k1 = v1 import ConfigParser config = ConfigParser.ConfigParser()config.read('i.cfg') # ########## 读 ###########secs = config.sections()#print secs#options = config.options('group2')#print options #item_list = config.items('group2')#print item_list #val = config.get('group1','key')#val = config.getint('group1','key') # ########## 改写 ###########sec = config.remove_section('group1')#config.write(open('i.cfg', "w")) #sec = config.has_section('wupeiqi')#sec = config.add_section('wupeiqi')#config.write(open('i.cfg', "w")) #config.set('group2','k1',11111)#config.write(open('i.cfg', "w")) #config.remove_option('group2','age')#config.write(open('i.cfg', "w"))
hashlib模块
用于加密相关的操作3.x里代替了md5模块和sha模块主要提供 SHA1, SHA224, SHA256, SHA384, SHA512 MD5 算法
import hashlib m = hashlib.md5()m.update(b"Hello")m.update(b"It's me")print(m.digest())m.update(b"It's been a long time since last time we ...") print(m.digest()) #2进制格式hashprint(len(m.hexdigest())) #16进制格式hash'''def digest(self, *args, **kwargs): # real signature unknown """ Return the digest value as a string of binary data. """ pass def hexdigest(self, *args, **kwargs): # real signature unknown """ Return the digest value as a string of hexadecimal digits. """ pass '''import hashlib # ######## md5 ######## hash = hashlib.md5()hash.update('admin')print(hash.hexdigest()) # ######## sha1 ######## hash = hashlib.sha1()hash.update('admin')print(hash.hexdigest()) # ######## sha256 ######## hash = hashlib.sha256()hash.update('admin')print(hash.hexdigest()) # ######## sha384 ######## hash = hashlib.sha384()hash.update('admin')print(hash.hexdigest()) # ######## sha512 ######## hash = hashlib.sha512()hash.update('admin')print(hash.hexdigest())
还不够吊python 还有一个 hmac 模块它内部对我们创建 key 和 内容 再进行处理然后再加密
import hmach = hmac.new('wueiqi')h.update('hellowo')print h.hexdigest()
更多关于md5,sha1,sha256等介绍的文章看这里https://www.tbs-certificates.co.uk/FAQ/en/sha256.html
Subprocess模块
The subprocess module allows you to spawn new processes, connect to their input/output/error pipes, and obtain their return codes. This module intends to replace several older modules and functions:
os.systemos.spawn*
The recommended approach to invoking subprocesses is to use the run() function for all use cases it can handle. For more advanced use cases, the underlying Popen interface can be used directly.
The run() function was added in Python 3.5; if you need to retain compatibility with older versions, see the Older high-level API section.
subprocess.run(args, *, stdin=None, input=None, stdout=None, stderr=None, shell=False, timeout=None, check=False)
Run the command described by args. Wait for command to complete, then return a CompletedProcess instance.
The arguments shown above are merely the most common ones, described below in Frequently Used Arguments (hence the use of keyword-only notation in the abbreviated signature). The full function signature is largely the same as that of the Popen constructor - apart from timeout, input and check, all the arguments to this function are passed through to that interface.
This does not capture stdout or stderr by default. To do so, pass PIPE for the stdout and/or stderr arguments.
The timeout argument is passed to Popen.communicate(). If the timeout expires, the child process will be killed and waited for. The TimeoutExpired exception will be re-raised after the child process has terminated.
The input argument is passed to Popen.communicate() and thus to the subprocess’s stdin. If used it must be a byte sequence, or a string if universal_newlines=True. When used, the internal Popen object is automatically created withstdin=PIPE, and the stdin argument may not be used as well.
If check is True, and the process exits with a non-zero exit code, a CalledProcessError exception will be raised. Attributes of that exception hold the arguments, the exit code, and stdout and stderr if they were captured.
>>> subprocess.run(["ls", "-l"]) # doesn't capture outputCompletedProcess(args=['ls', '-l'], returncode=0) >>> subprocess.run("exit 1", shell=True, check=True)Traceback (most recent call last): ...subprocess.CalledProcessError: Command 'exit 1' returned non-zero exit status 1 >>> subprocess.run(["ls", "-l", "/dev/null"], stdout=subprocess.PIPE)CompletedProcess(args=['ls', '-l', '/dev/null'], returncode=0,stdout=b'crw-rw-rw- 1 root root 1, 3 Jan 23 16:23 /dev/null\n')
调用subprocess.run(...)是推荐的常用方法在大多数情况下能满足需求但如果你可能需要进行一些复杂的与系统的交互的话你还可以用subprocess.Popen(),语法如下
p = subprocess.Popen("find / -size +1000000 -exec ls -shl {} \;",shell=True,stdout=subprocess.PIPE)print(p.stdout.read())
可用参数
-
argsshell命令可以是字符串或者序列类型如list元组
bufsize指定缓冲。0 无缓冲,1 行缓冲,其他 缓冲区大小,负值 系统缓冲
stdin, stdout, stderr分别表示程序的标准输入、输出、错误句柄
preexec_fn只在Unix平台下有效用于指定一个可执行对象callable object它将在子进程运行之前被调用
close_sfs在windows平台下如果close_fds被设置为True则新创建的子进程将不会继承父进程的输入、输出、错误管道。
所以不能将close_fds设置为True同时重定向子进程的标准输入、输出与错误(stdin, stdout, stderr)。shell同上
cwd用于设置子进程的当前目录
env用于指定子进程的环境变量。如果env = None子进程的环境变量将从父进程中继承。
universal_newlines不同系统的换行符不同True -> 同意使用 \n
startupinfo与createionflags只在windows下有效
将被传递给底层的CreateProcess()函数用于设置子进程的一些属性如主窗口的外观进程的优先级等等
终端输入的命令分为两种
输入即可得到输出如ifconfig
输入进行某环境依赖再输入如python
需要交互的命令示例
import subprocess obj = subprocess.Popen(["python"], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)obj.stdin.write('print 1 \n ')obj.stdin.write('print 2 \n ')obj.stdin.write('print 3 \n ')obj.stdin.write('print 4 \n ') out_error_list = obj.communicate(timeout=10)print out_error_list
logging模块
很多程序都有记录日志的需求并且日志中包含的信息即有正常的程序访问日志还可能有错误、警告等信息输出python的logging模块提供了标准的日志接口你可以通过它存储各种格式的日志logging的日志可以分为 debug(), info(), warning(), error() and critical() 5个级别下面我们看一下怎么用。
最简单用法
import logging logging.warning("user [alex] attempted wrong password more than 3 times")logging.critical("server is down") #输出WARNING:root:user [alex] attempted wrong password more than 3 timesCRITICAL:root:server is down
看一下这几个日志级别分别代表什么意思
| Level | When it’s used |
|---|---|
DEBUG |
Detailed information, typically of interest only when diagnosing problems. |
INFO |
Confirmation that things are working as expected. |
WARNING |
An indication that something unexpected happened, or indicative of some problem in the near future (e.g. ‘disk space low’). The software is still working as expected. |
ERROR |
Due to a more serious problem, the software has not been able to perform some function. |
CRITICAL |
A serious error, indicating that the program itself may be unable to continue running. |
如果想把日志写到文件里也很简单
import logging logging.basicConfig(filename='example.log',level=logging.INFO)logging.debug('This message should go to the log file')logging.info('So should this')logging.warning('And this, too')
其中下面这句中的level=loggin.INFO意思是把日志纪录级别设置为INFO也就是说只有比日志是INFO或比INFO级别更高的日志才会被纪录到文件里在这个例子 第一条日志是不会被纪录的如果希望纪录debug的日志那把日志级别改成DEBUG就行了。
logging.basicConfig(filename='example.log',level=logging.INFO)
感觉上面的日志格式忘记加上时间啦日志不知道时间怎么行呢下面就来加上!
import logginglogging.basicConfig(format='%(asctime)s %(message)s', datefmt='%m/%d/%Y %I:%M:%S %p')logging.warning('is when this event was logged.') #输出12/12/2010 11:46:36 AM is when this event was logged.
如果想同时把log打印在屏幕和文件日志里就需要了解一点复杂的知识 了
Loggers expose the interface that application code directly uses.
Handlers send the log records (created by loggers) to the appropriate destination.
Filters provide a finer grained facility for determining which log records to output.
Formatters specify the layout of log records in the final output.
import logging #create loggerlogger = logging.getLogger('TEST-LOG')logger.setLevel(logging.DEBUG) # create console handler and set level to debugch = logging.StreamHandler()ch.setLevel(logging.DEBUG) # create file handler and set level to warningfh = logging.FileHandler("access.log")fh.setLevel(logging.WARNING)# create formatterformatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s') # add formatter to ch and fhch.setFormatter(formatter)fh.setFormatter(formatter) # add ch and fh to loggerlogger.addHandler(ch)logger.addHandler(fh) # 'application' codelogger.debug('debug message')logger.info('info message')logger.warn('warn message')logger.error('error message')logger.critical('critical message')
re模块
常用正则表达式符号
'.' 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'^' 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)'$' 匹配字符结尾或e.search("foo$","bfoo\nsdfsf",flags=re.MULTILINE).group()也可以'*' 匹配*号前的字符0次或多次re.findall("ab*","cabb3abcbbac") 结果为['abb', 'ab', 'a']'+' 匹配前一个字符1次或多次re.findall("ab+","ab+cd+abb+bba") 结果['ab', 'abb']'?' 匹配前一个字符1次或0次'{m}' 匹配前一个字符m次'{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']'|' 匹配|左或|右的字符re.search("abc|ABC","ABCBabcCD").group() 结果'ABC''(...)' 分组匹配re.search("(abc){2}a(123|456)c", "abcabca456c").group() 结果 abcabca456c '\A' 只从字符开头匹配re.search("\Aabc","alexabc") 是匹配不到的'\Z' 匹配字符结尾同$'\d' 匹配数字0-9'\D' 匹配非数字'\w' 匹配[A-Za-z0-9]'\W' 匹配非[A-Za-z0-9]'s' 匹配空白字符、\t、\n、\r , re.search("\s+","ab\tc1\n3").group() 结果 '\t' '(?P<name>...)' 分组匹配 re.search("(?P<province>[0-9]{4})(?P<city>[0-9]{2})(?P<birthday>[0-9]{4})","371481199306143242").groupdict("city") 结果{'province': '3714', 'city': '81', 'birthday': '1993'}
最常用的匹配语法
re.match 从头开始匹配re.search 匹配包含re.findall 把所有匹配到的字符放到以列表中的元素返回re.splitall 以匹配到的字符当做列表分隔符re.sub 匹配字符并替换
反斜杠的困扰
与大多数编程语言相同正则表达式里使用"\"作为转义字符这就可能造成反斜杠困扰。假如你需要匹配文本中的字符"\"那么使用编程语言表示的正则表达式里将需要4个反斜杠"\\\\"前两个和后两个分别用于在编程语言里转义成反斜杠转换成两个反斜杠后再在正则表达式里转义成一个反斜杠。Python里的原生字符串很好地解决了这个问题这个例子中的正则表达式可以使用r"\\"表示。同样匹配一个数字的"\\d"可以写成r"\d"。有了原生字符串你再也不用担心是不是漏写了反斜杠写出来的表达式也更直观。
仅需轻轻知道的几个匹配模式
re.I(re.IGNORECASE): 忽略大小写括号内是完整写法下同M(MULTILINE): 多行模式改变'^'和'$'的行为参见上图S(DOTALL): 点任意匹配模式改变'.'的行为
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