Python Basic Note

Occasionally do something with Python, with a long time, and do not remember, and sometimes even the basic grammar are forgotten, here recorded in a piece of paper, convenient to view. Also covers more practical content, easy to twist (I did not write wrong bar 650) this.width=650; "src=" Http://img.baidu.com/hi/jx2/j_0059.gif "alt=" J_0059.gif "/>"

The code snippet is mainly excerpted from some Python code written in the previous period.

• Python Help

>>> python ("subprocess")

Help is important, Linux programmers, you know.

• Python Tutorial

https://docs.python.org/2/tutorial/

Beginner python people with this good, computer field, do not understand Google tutorial, you also know 650) this.width=650; "src=" Http://img.baidu.com/hi/jx2/j_0028.gif "alt = "J_0028.gif"/>

• Framework

1. Inherit, to write bigger things, object-oriented can not be less

Import subprocess  class virtualcommand ():          def __init__ (self):                  self._cmdstr = None                  pass           def cmdstr (self):                  return self._cmdstr           Def execute (self):                  return true  class command (Virtualcommand):          def __init__ (self, cmdstr= "Echo hello"):  # default  value to cmdstr &Nbsp;               virtualcommand. __init__ (self)     # call init of parent                  self._cmdstr = cmdstr.strip ( )           # called by task methods,  and can be inheritted         def  Execute (self, stdin=none):                  cmd = self._cmdstr.split (" ")                   p = subprocess. Popen (Cmd, stdin=stdin)                   p.wait ()                  return True   if __name__ ==  "__main__":       #main  entry          cmd = command ("ls")           cmd.execute ()

2. Input and flow control basic, which sometimes doesn't even remember.

if __name__ ==  "__main__":       #main  entry          x = int (Raw_input ("Please enter an integer:   "))          if x < 0:                  print  "Negative"          elif x == 0:                  print  "Zero"           else:                     print  "More"                             str =  "ThiS is a line "         for word in  Str.split ():                  print word          for i in range (Ten):                  print i          i = 0          while i < 10:                  print i                  i += 1

3. File operation, string to int, 2d array usage

if __name__ ==  "__main__":          m = [ [0 for x in range (6)] for x in range (8)]  #  Initialization of 2d array        with open ("AA")  as f:                  content = f.readlines ()          i =  0         for line in content:                  la =  Line.split (",")                   m[cnt][0] = int (la[0])    #received                &nBsp;  m[cnt][1] = int (la[1])    #injected           ... ...                 cnt += 1

 
4. Input parameters, signal, dictionary
 

import sys import signal import time  class generator:      mod_name =  ' Generator '      running = True           help =  "" "usage: snorttf.py [ parameter=value] parameters:     hs         http speed (default is 1000)      ds         dns speed (default is 10)      ss         smtp speed (default is 10)      server         smtp server      "" "       args = {          ' HS '  :   '    &nbs ',p;      ' ds '   :  ',                ' ss '  :  ',                  "Server"  :  "test11"           }      def __init__ (Self, args):          self.get_input_param (args)                          def  get_input_param (Self, input_args):          arg_num  = len (Input_args)          for i in  Range (1, arg_num):             arg  = input_args[i]  &nBsp;          elms = arg.split (' = ')               if elms[0] ==  ' Help ':                  print  self.help                  sys.exit (0)  #            print  Elms             if elms[0] in  self.args and len (ELMS)  == 2:                  self.args[elms[0]] = elms[1]              else:                  print  ' input wrong argument: ', arg                  print self.help                  sys.exit (0)                                      def check_parameters ( Self):          self.httpspeed = int (self.args[' HS ')          self.dnsspeed = int (self.args[' DS ')           self.smtpspeed = int (self.args[' SS '])           self.mailserver = self.args[' Server ']           pass      def run_client (self):          self.check_parameters ()          print  "HS:   " + str (self.httpspeed)  + "  ds:  " + str (self.dnsspeed)  +  \                  "  ss:  " + str (self.smtpspeed)  + "  server:  " + self.mailserver           #TODO           while self.running:             # Todo             time.sleep (1)           print  "Exit"   if __name__ ==  "__main__ ":    &Nbsp;     def signal_handler (Signal, frame):              Generator.running = False           signal.signal (signal. Sigint, signal_handler)          g = generator ( SYS.ARGV)          g.run_client ()

• Basic

1. List
# 2d list, Method Len (), append ()

>>> q = [2, 3]>>> p = [1, q, 4]>>> len (p) 3>>> p[1][2, 3]>>> p[1][0]2>>& Gt P[1].append (' Xtra ') # See section 5.1>>> p[1, [2, 3, ' Xtra '], 4]# method Sort () >>> a = [66.25, 333, 333, 1, 1234.5]>>> a.sort () >>> a[1, 66.25, 333, 333, 1234.5]

# as Stack

>>> stack = [3, 4, 5]>>> stack.append (6) >>> Stack.append (7) >>> stack[3, 4, 5, 6, 7]> ;>> Stack.pop () 7

#As Queue
#from Collections Import Deque

>>> queue = deque (["Eric",  "John",  "Michael"]) >>> queue.append ("Terry")            # Terry arrives>> > queue.append ("Graham")           # graham  arrives>>> queue.popleft ()                   # the first to arrive now leaves ' Eric ' >>> queue.popleft ()                   # the second to arrive now leaves ' John ' >> > queue                            # remaining queue in  order of arrivaldeque([' Michael ',  ' Terry ',  ' Graham ']) 

2. SSH through Paramiko

SSH = Paramiko. Sshclient () Ssh.load_system_host_keys () Ssh.set_missing_host_key_policy (Paramiko. Autoaddpolicy ()) #WarningPolicy) Ssh.connect (host, port, username, password) ssh.exec_command (SELF._CMDSTR)

3. Thread

Thread.start_new_thread (Print_log, ("Out", Self._aout))

4. XML process

Import Xml.etree.ElementTree as Etdef get_config_env (path): Tree = Et.parse (path) root = Tree.getroot () for CH ILD in Root:print Child.tag, Child.attrib, Child.text

5. Exception
Here try to execute task, if get any execption, perform term () to terminate any resources

Try:task.execute () except:task.term () Raise

Here show an example of throw execption,

Try:raise nameerror (' Hithere ') except Nameerror:print ' an exception flew by! ' Raise

• Skills

1. When a script file is used, it's sometimes useful to being able to run the script and enter interactive mode afterwards. This can is done by passing-i before the script.

2. Installation
Yum Install Python-setuptools # this install Easy_install
Easy_install Paramiko # This install any modules

This article is from the "Summit" blog, make sure to keep this source http://jiangjqian.blog.51cto.com/1040847/1665946

Python Basic Note