常用python编程模板汇总
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+=chunk
finally:
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+=line
finally:
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 MySQLdb
DB_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 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()
break
tcpSerSock.close()
2、客户端
from socket import *
HOST = 'localhost'
PORT = 21568
BUFSIZ = 1024
ADDR = (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 data
except:
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().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
还请大家积极补充！
