Two common modules in Python

Explanation of the Log module

1 Python uses the logging module to log logs involving four main classes, which are best used in the official documentation:2 3 logger provides an interface API that the application can use directly;4 handler sends the log record (created by logger) to the appropriate destination output;5 Formatter determining the final output format of the log record6 Filter provides a fine-grained device to determine which log record to output;7 8 Logger9 Each program obtains a logger before outputting the information. Logger usually corresponds to the module name of the program,Tensuch as the Chat tool graphical interface module can get its logger:log=Logging.getlogger ("Chat.gui") One  A You can also bind handler and filters - Logger.setlevel (LEL): Specifies the lowest log level, and the level below LEL is ignored. Debug is the lowest built-in level, critical is the highest - Logger.addfilter (filt), Logger.removefilter (filt): Add or remove the specified filter the Logger.addhandler (HDLR), Logger.removehandler (HDLR): Add or remove the specified handler - multiple handler can be attached to each logger. Next, let's introduce some common handler: - logging. Streamhandler uses this handler to output information to any file object, such as Sys.stdout or Sys.stderr.  - logging. Filehandler and Streamhandler are similar for outputting log information to a file. But Filehandler will open this file for you . + Logging.handlers.RotatingFileHandler - This handler is similar to the filehandler above, but it can manage the file size.  + when the file reaches a certain size, it automatically renames the current log file and then creates a new log file with the same name to continue the output.  A For example, the log file is Chat.log. When the chat.log reaches the specified size, atRotatingfilehandler automatically renamed the file to Chat.log.1.  -However, if chat.log.1 already exists, the Chat.log.1 will be renamed to Chat.log.2 first......  - Finally, re-create the Chat.log and continue to output the log information.  - function Format: Rotatingfilehandler (filename[, mode[, maxbytes[, Backupcount]]) maxbytes Maximum length backupcount number of files reserved - Logging.handlers.TimedRotatingFileHandler - This handler is similar to Rotatingfilehandler, but it does not determine when the log file is recreated by judging the file size. in instead, a new log file is created automatically at a certain time interval. The process of renaming is similar to Rotatingfilehandler, - However, the new file is not an additional number but the current time.  to its function is: timedrotatingfilehandler (filename [, when [, interval [, Backupcount]]) +when="s" seconds calculate interveal interval backupcount number of files reserved -s seconds M min h hours d days W per week (interval==0 o'clock on behalf of Monday) midnight every morning the Formatter Components * The formatter of the log is a separate component that can be combined with handler $FH = logging. Filehandler ("Access.log")Panax NotoginsengFormatter = logging. Formatter ('% (asctime) s-% (name) s-% (levelname) s-% (message) s') -Fh.setformatter (Formatter)#bind the Formmater to the FH. the If you want to filter the log content, you can customize a filter + classIgnorebackuplogfilter (logging. Filter): A     """ignore logs with DB backup""" the     defFilter (self, record):#fixed notation +         return   "DB Backup"  not inchrecord.getmessage () -  $ #Note that the filter function returns TRUE or False,logger determines whether this log is output based on this value $  - #then add this filter to the logger - #Logger.addfilter (Ignorebackuplogfilter ())

Description Parsing 

　

Import loggingfrom Logging Import handlers# set an output to Handlerlog_p_handler = logging on the screen. Streamhandler () # defines the Handlerlog_f_handler = logging of an input file. Filehandler ("Xx.log", encoding= "UTF8") # This is the example of that log truncation, truncated by length log_f_handler_1 = handlers. Rotatingfilehandler ("Xxx.log", maxbytes=10, backupcount=2, encoding= "UTF8") log_f_handler_1.setlevel (logging. WARNING) Log_f_handler.setlevel (logging. WARNING) # handler defines a log level log_p_handler.setlevel (logging.info) # for access to a file handler define a log level fm_p = logging. Formatter ("% (asctime) s-% (levelname) s->% (message) S", datefmt= "%y-%m-%d%i:%m:%s") # defines two formats Fm_f = logging. Formatter ("% (asctime) s-% (filename) s-% (levelname) s->% (message) S", datefmt= "%y-%m-%d%i:%m:%s") # Add format to Handler in Log_f_handler.setformatter (Fm_f) log_f_handler_1.setformatter (Fm_f) log_p_handler.setformatter (fm_p) Log = Logging.getlogger ("Test") # generates a log interface # adds its own defined handler to log Log.addhandler (Log_p_handler) Log.addhandler (log_f_ Handler) Log.addhandler (log_f_handler_1) # set log global logging level if not set the default warning level LOg.setlevel (Logging.info) log.info ("INFO log") log.warning ("Warn log") log.debug ("Debug Log") 

　　

The Subproess module provides a unified module to implement calls to system commands or scripts

# Three ways to execute commands # Subprocess.run (*popenargs, Input=none, Timeout=none, Check=false, **kwargs) #官方推荐 # subprocess.call (* Popenargs, Timeout=none, **kwargs) #跟上面实现的内容差不多, another way # #subprocess. Popen () #上面各种方法的底层封装 # Run's standard notation import subprocesssubprocess.run ([' DF ', '-h '], stderr=subprocess. PIPE, Stdout=subprocess. Pipe, Check=true) # parameter resolution: [' DF ', '-h '] List execution command subprocess will be stitched together stdout standard output =pipe pipe character Check True error # also can be with shell=true so you can  With direct write command: Subprocess.run (' Df-h|grep disk1 ', shell=true) # shell=true means that this command is delivered directly to the system and does not require Python to parse # Execute command, return command execution state, 0 or Non 0retcode = Subprocess.call (["LS", "-L"]) # Execute command, if command result is 0, return normally, otherwise throw exception subprocess.check_call (["LS", "-L"]) # 0# receive string Format command , returns the tuple form, the 1th element is the execution state, and the 2nd is the command result subprocess.getstatusoutput (' Ls/bin/ls ') # (0, '/bin/ls ') # Receive string Format command, and returns the result Subprocess.getoutput (' Ls/bin/ls ') # '/bin/ls ' # executes the command and returns the result, note that the result is returned, not printed, and the following example returns to Resres = Subprocess.check_output ([' ls ', '-l ']) # res= B ' Total 0\ndrwxr-xr-x-Alex Staff 408 2 11:05 oldboycrm\n ' # Popen will not wait for command execution to return results but return a handle to a call PO ll () method can be checkedThe specified state of a = subprocess. Popen (' Sleep ', shell=true, stdout=subprocess. PIPE) #这里还有其他方法 will not repeat it. # a.wait () A.kill () a.pid () # a.send_signal () a.terminate ()

Hashlib: For cryptographic related operations, instead of MD5 module and SHA module, mainly provides SHA1, SHA224, SHA256 , SHA384, SHA512, MD5 algorithm

Import hashlib# is used for cryptographic related operations, 3.x replaces the MD5 module and the SHA module, mainly provides SHA1, SHA224, SHA256, SHA384, SHA512, MD5 algorithm m=hashlib.md5 () m.update ( Bytes ("I", encoding= "UTF8")) m.update (b ' It is Me ') print ("Binary", M.digest ()) print ("Hex", M.hexdigest ()) # Although the above encryption algorithm is still very strong, but the time has the flaw, namely: through the collision library can reverse the solution. Therefore, it is necessary to add a custom key to the encryption algorithm to do encryption. Print ("". Center ("*")) M1=hashlib.md5 (bytes ("Encrypt on Build", encoding= "UTF8")) m1.update (bytes ("I", encoding= "UTF8")) M1.update (b ' It is Me ') print ("Binary", M.digest ()) print ("Hex", M.hexdigest ())

RE module: The regular expression is the string matching rules, in most programming languages have corresponding support, Python corresponding module is re

'.'default match any character except \ n, if flag Dotall is specified, matches any character, including line break#The ' ^ ' matches the beginning of the character, and if you specify the flags MULTILINE, this can also be matched on (r "^a", "\nabc\neee", Flags=re. MULTILINE)#' $ ' matches the end of the character, if specified by flags MULTILINE, Re.search (' foo.$ ', ' foo1\nfoo2\n ', re. MULTILINE). Group () will match to Foo1#' * ' matches the character before the * number 0 or more times, Re.search (' A * ', ' aaaabac ') result ' aaaa '#' + ' matches the previous character 1 or more times, Re.findall ("ab+", "Ab+cd+abb+bba") results [' AB ', ' ABB ']#'? ' Match the previous character 1 or 0 times, re.search (' B? ', ' Alex '). Group () match B 0 Times#' {m} ' matches the previous character m times, Re.search (' b{3} ', ' Alexbbbs '). Group () match to ' BBB '#' {n,m} ' matches the previous character N to M times, Re.findall ("ab{1,3}", "ABB ABC abbcbbb") Results ' ABB ', ' AB ', ' ABB ']#' | ' Match | left or | Right character, re.search ("abc| ABC "," ABCBABCCD "). Group () result ' ABC '#' (...) ' Group match, Re.search ("(ABC) {2}A (123|45)", "abcabca456c"). Group () Results for ' abcabca45 '# # #' \a ' matches only from the beginning of the character, Re.search ("\aabc", "ALEXABC") are not matched, equivalent to Re.match (' abc ', ' alexabc ') or ^#' \z ' matches the end of the character, same as $#' \d ' matches digital 0-9#' \d ' matches non-numeric#' \w ' match [a-za-z0-9]#' \w ' matches non-[a-za-z0-9]#' s ' matches whitespace characters, \ t, \ n, \ r, Re.search ("\s+", "Ab\tc1\n3"). Group () result ' \ t '# #' (? P<name>, ...) ' Group Matching Re.search (? P<province>[0-9]{4}) (? P<city>[0-9]{2}) (? P<BIRTHDAY>[0-9]{4}) "," 371481199306143242 "). Groupdict (" City " )#result {' Province ': ' 3714 ', ' City ': ' Bayi ', ' Birthday ': ' 1993 '}

Model Details

Import res = ' AB23CD121RF ' Res=re.match ("[0-9]", s) #从头开始匹配 match one on end print (res) res = Re.search ("[0-9]{2}", s) # match matches from all character matches An end of the print (RES) # object takes the value inside the group without an error, and the result needs to be judged if Res:print (Res.group ()) Else:print ("none!") Print (Re.findall ("[0-9]", s)) # match all matches and put it in the list print (Re.search (".", "AAA") # from the beginning to find any character returned to print (Re.search ("^a", "AA A ")) # equals match (' A ') print (Re.search (" ^ab "," Abaab ")) # equals match (' A ') print (Re.search (" ab+$ "," Abaabb ") # from the last search. Print at end of ABB (multiple B) (Re.search ("[a| A]lex "," Alexalex ")) #自己的理解就是拿着alex #或 Alex to find a match in the character to print (Re.search (" [a| A]lex "," Aaalex ")) s = ' 120980199612098769 ' #必须是字符匹配print (Re.search (" (\d{6}) (\d{4}) (\d{4}) ", s). Groups ()) # Group Matching print (Re.search (? P<province>\d{6}) (? P<year>\d{4}) (? P&LT;MOTHON&GT;\D{4}) ", s). Groupdict ()) F = open (" Contact. txt ", encoding=" GBK ") data = F.read () print (data) f.close () res = Re.findall ("(1\d{10})", data) # Mobile number print (res) s = "Alex22jack22rain33" Print (Re.split ("\d", s)) # split print in one format ( Re.split ("\d+", s)) s1= "Alex22jack22rain33#mock-oldboy" Print (Re.split ("\d+|#|-", S1) # The given character all matches successfully then returns the character otherwise 0# print (Re.fullmatch (' \[email  protected]\w+\. (com|cn|edu) ', ' [email protected] ') # Blur find the character that needs to be matched to replace print (Re.sub ("[\d+|#|-]", "_", S1)) s = ' 9-2*5/3+7/3*99/4* 2998+10*568/14 ' # Print (Re.split (' [\*\-/+] ', s)) #转义需要 \ to express print (Re.split (' [\*\-/+] ', S, maxsplit=2)) # Escape required \ to express maxspli T match before a few stops match # [' 9 ', ' 2 ', ' 5 ', ' 3 ', ' 7 ', ' 3 ', ' 99 ', ' 4 ', ' 2998 ', ' 10 ', ' 568 ', ' 14 ']

　　

Two common modules in Python