python编程常用总结

在我们编程时，有一些代码是固定的，例如Socket连接的代码，读取文件内容的代码，一般情况下我都是到网上搜一下然后直接粘贴下来改一改，当然如果你能自己记住所有的代码那更厉害，但是自己写毕竟不如粘贴来的快，而且自己写的代码还要测试，而一段经过测试的代码则可以多次使用，所以这里我就自己总结了一下python中常用的编程模板，如果还有哪些漏掉了请大家及时补充哈。

一、读写文件

1、读文件

（1）、一次性读取全部内容

filepath='D:/data.txt' #文件路径with open(filepath, 'r') as f:    print f.read()

（2）读取固定字节大小

# -*- 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+=chunkfinally:    f.close()    print content

（3）每次读取一行

# -*- 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+=linefinally:    f.close()    print content

（4）一次读取所有的行

# -*- 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、写文件

# -*- 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会在文件末尾追加    f.write('1234')

二、连接Mysql数据库

1、连接

#!/usr/bin/python# -*- coding: UTF-8 -*-import MySQLdbDB_URL='localhost'USER_NAME='root'PASSWD='1234'DB_NAME='test'# 打开数据库连接db = MySQLdb.connect(DB_URL,USER_NAME,PASSWD,DB_NAME)# 使用cursor()方法获取操作游标 cursor = db.cursor()# 使用execute方法执行SQL语句cursor.execute("SELECT VERSION()")# 使用 fetchone() 方法获取一条数据库。data = cursor.fetchone()print "Database version : %s " % data# 关闭数据库连接db.close()

2、创建表

#!/usr/bin/python# -*- coding: UTF-8 -*-import MySQLdb# 打开数据库连接db = MySQLdb.connect("localhost","testuser","test123","TESTDB" )# 使用cursor()方法获取操作游标 cursor = db.cursor()# 如果数据表已经存在使用 execute() 方法删除表。cursor.execute("DROP TABLE IF EXISTS EMPLOYEE")# 创建数据表SQL语句sql = """CREATE TABLE EMPLOYEE (         FIRST_NAME  CHAR(20) NOT NULL,         LAST_NAME  CHAR(20),         AGE INT,           SEX CHAR(1),         INCOME FLOAT )"""cursor.execute(sql)# 关闭数据库连接db.close()

3、插入

#!/usr/bin/python# -*- coding: UTF-8 -*-import MySQLdb# 打开数据库连接db = MySQLdb.connect("localhost","testuser","test123","TESTDB" )# 使用cursor()方法获取操作游标 cursor = db.cursor()# SQL 插入语句sql = """INSERT INTO EMPLOYEE(FIRST_NAME,         LAST_NAME, AGE, SEX, INCOME)         VALUES ('Mac', 'Mohan', 20, 'M', 2000)"""try:   # 执行sql语句   cursor.execute(sql)   # 提交到数据库执行   db.commit()except:   # Rollback in case there is any error   db.rollback()# 关闭数据库连接db.close()

4、查询

#!/usr/bin/python# -*- coding: UTF-8 -*-import MySQLdb# 打开数据库连接db = MySQLdb.connect("localhost","testuser","test123","TESTDB" )# 使用cursor()方法获取操作游标 cursor = db.cursor()# SQL 查询语句sql = "SELECT * FROM EMPLOYEE \       WHERE INCOME > '%d'" % (1000)try:   # 执行SQL语句   cursor.execute(sql)   # 获取所有记录列表   results = cursor.fetchall()   for row in results:      fname = row[0]      lname = row[1]      age = row[2]      sex = row[3]      income = row[4]      # 打印结果      print "fname=%s,lname=%s,age=%d,sex=%s,income=%d" % \             (fname, lname, age, sex, income )except:   print "Error: unable to fecth data"# 关闭数据库连接db.close()

5、更新

#!/usr/bin/python# -*- coding: UTF-8 -*-import MySQLdb# 打开数据库连接db = MySQLdb.connect("localhost","testuser","test123","TESTDB" )# 使用cursor()方法获取操作游标 cursor = db.cursor()# SQL 更新语句sql = "UPDATE EMPLOYEE SET AGE = AGE + 1                          WHERE SEX = '%c'" % ('M')try:   # 执行SQL语句   cursor.execute(sql)   # 提交到数据库执行   db.commit()except:   # 发生错误时回滚   db.rollback()# 关闭数据库连接db.close()

三、Socket

1、服务器

from socket import *from time import ctimeHOST = ''PORT = 21568BUFSIZ = 1024ADDR = (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()              breaktcpSerSock.close()

2、客户端

from socket import *HOST = 'localhost'PORT = 21568BUFSIZ = 1024ADDR = (HOST, PORT)tcpCliSock = socket(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 dataexcept:    tcpCliSock.close() 

四、多线程

import time, threading# 新线程执行的代码: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().nameprint 'thread %s is running...' % threading.current_thread().namet = threading.Thread(target=loop, name='LoopThread')t.start()t.join()print 'thread %s ended.' % threading.current_thread().name

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