Python的世界

可爱的Python——足够简单问题的解决之道

假设我们有这么一项任务:简单测试局域网中的电脑是否连通.这些电脑的ip范围从192.168.0.101到192.168.0.200.

import subprocesscmd="cmd.exe"begin=101end=200while begin<end:p=subprocess.Popen(cmd,shell=True,stdout=subprocess.PIPE,stdin=subprocess.PIPE,stderr=subprocess.PIPE)p.stdin.write("ping 192.168.1."+str(begin)+"\n")p.stdin.close()p.wait()print "execution result: %s"%p.stdout.read()

1、搭建开发环境

linux:    

1、安装开发环境

sudoapt-getinstallopenjdk-6-jdk

sudoapt-getinstalleclipse

python一般Linux自带

在eclipase中，InstallNewSoftware 

这是地址：Location：http://pydev.org/updates（PyDev的更新地址）

选择PyDev下的PyDevforEclipse，其他的不选

安装之后重启eclipse

2、 配置PyDev插件

 

PyDev->Interpreter-Python，New一个Python解释器，填上解释器名字和路径，路径选相应的python.exe。

 File->New->Project，选PyDev下的PyDevProject，Grammer和Interpreter选相应的版本，Finish。

 

windows:

1、下载工具jthon(http://wiki.python.org/jython/DownloadInstructions)，下载后双击执行该jar包.   第一步时选择所有,包括所有源. 

2、在DOS命令窗口执行批处理。 

cmd进入命令行状态。到安装目录c:/jthon2.5.5/执行jython.bat。 

3、在eclipse中安装jthon插件 

在help->softupdate->add sites 输入:windowhttp://pydev.sourceforge.net/updates/ 下载完后。选中这些下载选项。后点直接安装

4、配置jython. 

在window-->属性->pydev->interpreter-jython->new->浏览你安装jthon的目录（c://jython2.5.5.)指向jython.jar.点击应用。然后点击ok. 

2、Hello Python

print "Hello Python"

Python就是如此神奇

3、国际化的语言支持

# -*- coding: GBK -*- 

print "欢迎来的Python的世界!" # 使用中文

raw_input("Press enter key to close this window");

可以这样设置语言的支持

4、方便易用的计算器

a=100.0

b=201.1

c=2343

print (a+b+c)/c

python就是计算器？

5 、字符串

打印出预定义输出格式的字符串:

print """Usage: thingy [OPTIONS]-h Display this usage message-H hostname Hostname to connect to"""

Python怎么访问字符串呢？

word="abcdefg"a=word[2]print "a is: "+ab=word[1:3]print "b is: "+b # index 1 and 2 elements of word.c=word[:2]print "c is: "+c # index 0 and 1 elements of word.d=word[0:]print "d is: "+d # All elements of word.e=word[:2]+word[2:]print "e is: "+e # All elements of word.f=word[-1]print "f is: "+f # The last elements of word.g=word[-4:-2]print "g is: "+g # index 3 and 4 elements of word.h=word[-2:]print "h is: "+h # The last two elements.i=word[:-2]print "i is: "+i # Everything except the last two charactersl=len(word)print "Length of word is: "+ str(l)

请注意ASCII和UNICODE字符串的区别:

print "Input your Chinese name:"s=raw_input("Press enter to be continued");print "Your name is  : " +s;l=len(s)print "Length of your Chinese name in asc codes is:"+str(l);a=unicode(s,"GBK")l=len(a)print "I'm sorry we should use unicode char!Characters number of your Chinese \name in unicode is:"+str(l);

6 、列表 

word=['a','b','c','d','e','f','g']a=word[2]print "a is: "+ab=word[1:3]print "b is: "print b # index 1 and 2 elements of word.c=word[:2]print "c is: "print c # index 0 and 1 elements of word.d=word[0:]print "d is: "print d # All elements of word.e=word[:2]+word[2:]print "e is: "print e # All elements of word.f=word[-1]print "f is: "print f # The last elements of word.g=word[-4:-2]print "g is: "print g # index 3 and 4 elements of word.h=word[-2:]print "h is: "print h # The last two elements.i=word[:-2]print "i is: "print i # Everything except the last two charactersl=len(word)print "Length of word is: "+ str(l)print "Adds new element"word.append('h')print word

Python有着简易方便的数据类型

7、条件和循环语句

# Multi-way decisionx=int(raw_input("Please enter an integer:"))if x<0:x=0print "Negative changed to zero"elif x==0:print "Zero"else:print "More"# Loops Lista = ['cat', 'window', 'defenestrate']for x in a:print x, len(x)

Python是艺术家！

8、函数

# Define and invoke function.def sum(a,b):return a+bfunc = sumr = func(5,6)print r# Defines function with default argumentdef add(a,b=2):return a+br=add(1)print rr=add(1,5)print r并且,介绍一个方便好用的函数:# The range() functiona =range(5,10)print aa = range(-2,-7)print aa = range(-7,-2)print aa = range(-2,-11,-3) # The 3rd parameter stands for stepprint a

Python竟然拥有如此完美的身材

9、文件I/O

spath="D:/download/baa.txt"f=open(spath,"w") # Opens file for writing.Creates this file doesn't exist.f.write("First line 1.\n")f.writelines("First line 2.")f.close()f=open(spath,"r") # Opens file for readingfor line in f:print linef.close()

处理文件是不是很简单？

10、异常处理

s=raw_input("Input your age:")if s =="":raise Exception("Input must no be empty.")try:i=int(s)except ValueError:print "Could not convert data to an integer."except:print "Unknown exception!"else: # It is useful for code that must be executed if the try clause does not raise an exceptionprint "You are %d" % i," years old"finally: # Clean up actionprint "Goodbye!"

Python这样来解决异常

11、类和继承

class Base:

def __init__(self):

self.data = []

def add(self, x):

self.data.append(x)

def addtwice(self, x):

self.add(x)

self.add(x)

# Child extends Base

class Child(Base):

def plus(self,a,b):

return a+b

oChild =Child()

oChild.add("str1")

print oChild.data

print oChild.plus(2,3)

Pyhon最可爱的面向对象语言

12、包机制

每一个.py文件称为一个module,module之间可以互相导入.

# a.pydef add_func(a,b):return a+b# b.pyfrom a import add_func # Also can be : import aprint "Import add_func from module a"print "Result of 1 plus 2 is: "print add_func(1,2) # If using "import a" , then here should be "a.add_func"

带有文件层级结构的导包

parent --__init_.py--child-- __init_.py--a.pyb.py

Python如何找到我们定义的module?

在标准包sys中,path属性记录了Python的包路径.

import sysprint sys.path

通常我们可以将module的包路径放到环境变量PYTHONPATH中,该环境变量会自动添加到sys.path属性.另一种方便的方法是编程中直接指定我们的module路径到sys.path 中:

import sys

sys.path.append('D:\\download')from parent.child.a import add_funcprint sys.pathprint "Import add_func from module a"print "Result of 1 plus 2 is: "print add_func(1,2)