Python Programming common summary __ Programming

When we are programming, some of the code is fixed, such as socket connection code, read the file contents of the code, generally I will search the Internet and then directly paste down to change, of course, if you can remember all the code that more powerful, but their own writing is not as fast as pasting, and write their own code to test, and a test of the code can be used many times, so here I summed up a few of the common programming templates in Python, if there are any missing and please be timely to add ha.

I. Read and write documents

1, read the file

(1), read all content at once

Filepath= ' D:/data.txt ' #文件路径

with open (filepath, ' R ') as F:
    print F.read ()

(2) Read fixed byte size

#-*-Coding:utf-8-*-

filepath= ' d:/data.txt ' #文件路径

f = open (filepath, ' R ')
content= ""
try:
    while True:
        chunk = F.read (8)
        if not chunk:
            break
        content+=chunk
finally:
    f.close ()
    Print content

(3) read one line at a time

#-*-Coding:utf-8-*-

filepath= ' d:/data.txt ' #文件路径

f = open (filepath, "R")
content= ""
try:
    while True: Line
        = F.readline ()
        if not line: Break
        Content+=line
finally:
    f.close ()
    Print Content

(4) Read all rows at once

#-*-Coding:utf-8-*-

filepath= ' d:/data.txt ' #文件路径

with open (filepath, "R") as F:
    txt_list = F.readlines ()

for i in txt_list:
    print I,

2, write the document

#-*-Coding:utf-8-*-

filepath= ' d:/data1.txt ' #文件路径 with

open (filepath, "w") as F: #w会覆盖原来的文件, A will append at the end of the file
    f.write (' 1234 ')

Second, the connection MySQL database

1, Connection

#!/usr/bin/python
#-*-coding:utf-8-*-import mysqldb db_url= ' localhost ' user_name= '
root '
passwd= ' 1234 '
db_name= ' test '

# Open database connection
DB = MySQLdb.connect (db_url,user_name,passwd,db_name)

# Use the cursor () method to get 
the action cursor cursor = Db.cursor ()

# Use the Execute method to execute the SQL statement
cursor.execute ("Select VERSION ()")

# Use the Fetchone () method to get a database.
data = Cursor.fetchone ()

print "Database version:%s"% Data

# Close DB connection
Db.close ()

2. Create a table

#!/usr/bin/python
#-*-coding:utf-8-*-

import mysqldb

# Open database connection
db = MySQLdb.connect ("localhost", " TestUser "," test123 "," TestDB ")

# Use the cursor () method to get the action cursor 
cursor = db.cursor ()

# If the datasheet already exists use the Execute () method to delete the table.
cursor.execute ("DROP TABLE IF EXISTS employee")

# Create datasheet SQL statement sql = "" Create
Table EMPLOYEE (
         first_ NAME  Char not NULL,
         last_name  char (m), age
         INT,  
         SEX char (1),
         income FLOAT) ""

cursor.execute (SQL)

# Close database connection
db.close ()

3. Insert

#!/usr/bin/python
#-*-coding:utf-8-*-

import mysqldb

# Open database connection
db = MySQLdb.connect ("localhost", " TestUser "," test123 "," TestDB ")

# Use Cursor () method to get action cursor 
cursor = db.cursor ()

# SQL INSERT statement
sql = '" ' Insert Into the EMPLOYEE (first_name,
         last_name, age, SEX, income)
         VALUES (' Mac ', ' Mohan ', ', ', ' M ', Watts) "" "
Try:
   # Execute SQL statement
   cursor.execute (SQL)
   # Commit to Database Execution
   db.commit ()
except:
   # Rollback in case there Are any error
   Db.rollback ()

# Close database connection
db.close ()

4, Inquiry

#!/usr/bin/python
#-*-coding:utf-8-*-

import mysqldb

# Open database connection
db = MySQLdb.connect ("localhost", " TestUser "," test123 "," TestDB ")

# Use Cursor () method to get action cursor 
cursor = db.cursor ()

# SQL query statement
sql = ' SELECT * FROM EMPLOYEE \
       WHERE income > '%d '% (1000)
try:
   # Execute SQL statement
   cursor.execute (SQL)
   # get all records list
   Results = Cursor.fetchall () for
   row in results:
      fname = row[0]
      lname = row[1] Age
      = row[2]
      sex = ROW[3]
      income = row[4]
      # Print the result print
      "fname=%s,lname=%s,age=%d,sex=%s,income=%d"%
             (fname, lname , age, sex, income)
except:
   print "error:unable to FECTH data"

# Close database connection
db.close ()

5, Update

#!/usr/bin/python
#-*-coding:utf-8-*-

import mysqldb

# Open database connection
db = MySQLdb.connect ("localhost", " TestUser "," test123 "," TestDB ")

# Use Cursor () method to get action cursor 
cursor = db.cursor ()

# SQL UPDATE statement
sql = ' Update EMPLOYEE SET age = age + 1
                          WHERE SEX = '%c '% (' M ')
try:
   # Execute SQL statement
   cursor.execute (SQL)
   # commit to Database execution C13/>db.commit ()
except:
   # rollback Db.rollback () # When an error occurs (
   )

# Close database connection
db.close ()

Third, Socket

1, Server

From socket import * from time
import ctime

HOST = '
PORT = 21568
bufsiz = 1024
ADDR = (HOST, PORT) 
  tcpsersock = socket (af_inet, sock_stream)
tcpsersock.bind (ADDR)
Tcpsersock.listen (5) while

True:
    print ' Waiting for connection ... '
    tcpclisock, addr = tcpsersock.accept ()  
    print ' ... connected from: ', Addr

    while True:
        try:
            data = TCPCLISOCK.RECV (bufsiz)  
            print ' < ', data
            tcpclisock.send (' [ %s]%s '% (CTime (), data)  
        except:
            print ' Disconnect from: ', addr
            tcpclisock.close ()
Tcpsersock.close ()

2. Client

From socket import *

HOST = ' localhost '
PORT = 21568
bufsiz = 1024
ADDR = (HOST, PORT)

Tcpclisock = Cket (Af_inet, Sock_stream)
tcpclisock.connect (ADDR)  

try: While
    True:
        data = raw_input (' > ')
        If data = "Close":
            break
        if not data:
            continue
        tcpclisock.send (data)  
        data = Tcpclisock.recv (Bufsiz)  
        Print Data
except:
    

Four, multithreading

Import time, Threading

# code for new thread execution:
def loop ():
    print ' thread%s is running ... '% threading.current_thread ().  Name
    n = 0
    while n < 5: n
        = n + 1
        print ' thread%s >>>%s '% (Threading.current_thread (). Name, N)
        time.sleep (1)
    print ' thread%s ended. '% Threading.current_thread (). Name

print ' thread%s is running ... ' % Threading.current_thread (). Name
t = Threading. Thread (Target=loop, name= ' Loopthread ')
T.start ()
t.join ()
print ' thread%s ended. '% Threading.current_thread (). Name

Reprint: http://blog.csdn.net/xingjiarong/article/details/50651235