思路:用shell编程.(Linux通常是bash而Windows是批处理脚本).例如,在Windows上用ping ip 的命令依次测试各个机器并得到控制台输出.由于ping通的时候控制台文本通常是"Reply from ... " 而不通的时候文本是"time out ... " ,所以,在结果中进行字符串查找,即可知道该机器是否连通.
实现:Java代码如下:
String cmd="cmd.exe ping "; String ipprefix="192.168.10."; int begin=101; int end=200; Process p=null;
for(int i=begin;i<end;i++){ p= Runtime.getRuntime().exec(cmd+i); String line =null; BufferedReader reader =new BufferedReader(new InputStreamReader(p.getInputStream())); while((line = reader.readLine()) !=null) { //Handling line , may logs it. } reader.close(); p.destroy(); }
print "欢迎来到奥运中国!" raw_input("Press enter key to close this window");
在你保存代码的时候,Python会提示你是否改变文件的字符集,结果如下:
# -*- coding: cp936 -*-
print "欢迎来到奥运中国!" raw_input("Press enter key to close this window");
将该字符集改为我们更熟悉的形式:
# -*- coding: GBK -*-
print "欢迎来到奥运中国!" # 使用中文的例子 raw_input("Press enter key to close this window");
程序一样运行良好.
2.3 方便易用的计算器
用微软附带的计算器来计数实在太麻烦了.打开Python解释器,直接进行计算:
a=100.0 b=201.1 c=2343 print (a+b+c)/c
2.4 字符串,ASCII和UNICODE
可以如下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 """
字符串是怎么访问的?请看这个例子:
word="abcdefg" a=word[2] print "a is: "+a b=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 characters l=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);
2.5 使用List
类似Java里的List,这是一种方便易用的数据类型:
word=['a','b','c','d','e','f','g'] a=word[2] print "a is: "+a b=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 characters l=len(word) print "Length of word is: "+ str(l) print "Adds new element" word.append('h') print word
2.6 条件和循环语句
# Multi-way decision x=int(raw_input("Please enter an integer:")) if x<0: x=0 print "Negative changed to zero"
elif x==0: print "Zero"
else: print "More"
# Loops List a = ['cat', 'window', 'defenestrate'] for x in a: print x, len(x)
2.7 如何定义函数
# Define and invoke function. def sum(a,b): return a+b
func = sum r = func(5,6) print r
# Defines function with default argument def add(a,b=2): return a+b r=add(1) print r r=add(1,5) print r
并且,介绍一个方便好用的函数:
# The range() function a =range(5,10) print a a = range(-2,-7) print a a = range(-7,-2) print a a = range(-2,-11,-3) # The 3rd parameter stands for step print a
2.8 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 reading
for line in f: print line
f.close()
2.9 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 exception print "You are %d"% i," years old" finally: # Clean up action print "Goodbye!"