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!
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