Python: python的简单表达式计算器
这是一个简单的表达式计算器, 不太懂用Tkinter写GUI, 参考了别人的代码
from __future__ import division
from Tkinter import Tk, Entry, Button, Label, mainloop
from tkFont import Font
def get_value ():
v = ''
try:
v = eval(text.get()) #use eval to calculate the vlaue of the text
except:
pass
if isinstance(v, (int, float, long)):
pass
else:
v = 'Error...'
label.config(text = v) #use config to change the text
top = Tk()
top.title("calculator")
ft = Font(family = 'Courier New', size = 12)
text = Entry(top, font = ft)
button = Button(top, text = 'Ok', command = get_value)
label = Label(text = '(+ - * / % **)', font = ft)
Enter = lambda x: x.keycode == 13 and get_value()
Key = lambda x: label.config(text = '(+ - * / % **)')
text.bind('<Key>', Enter) #when the key is enter, execute the function Enter
text.focus()
text.bind('<Button-1>', Key) #when click the left-key, execute the function Key
text.pack()
button.pack()
label.pack()
mainloop()
相关文档：
网络时间服务器 一般都遵循 RFC868 协议标准.
按该标准 附下面 Python 源码.
# -*- coding: utf-8 -*-
import socket,sys,time
#时间服务器
host = "stdtime.gov.hk"
#端口
port = 37
#时区
curtz = 8
#连接服务器,并接收返回
try:
host = socket.gethostbyname(host)
s = socket.socket(socket.AF_INET,soc ......
对数据库的操作基本分为三步：
连接数据库
根据需要执行SQL语句，接受返回值
关闭连接
我们正常的数据库应该都离不开这三步，下来说说如何使用python中的MySQLdb模块进行这些操作：
首先，我们需要把MySQLdb引入到程序中
import MySQLdb
然后开始数据库操作
1.数据库连接
conn = MySQLdb. ......
1.可执行程序
os.system('pgrep %s > %s' % (process, output))
pidfile = open("output", 'r')
totalpid = len(pidfile.readlines())
pidfile.close()
if totalpid == 0 :
&nbs ......
threading — Higher-level threading interface
This module constructs higher-level threading interfaces on top of the lower level _thread module. See also the queue module.
The dummy_threading module is provided for situations where threading cannot be used because _thread is missing.
......
multiprocessing — Process-based “threading” interface
Introduction
multiprocessing is a package that supports spawning processes using an API similar to the threading module. The multiprocessing package offers both local and remote concurrency, effectively side-stepping the Glo ......
