Python体验(01)变量、函数和基本控制语句

今天安装了Debian5，没想到基础安装的情况下居然会有python，于是安装试试这个传说中的语言。

下面通过一系列简单示例来体验，代码可以直接粘贴保存，都通过测试。

我参照pdf学习的,大家可以从这个地址下载pdf文件.

案例1：

#用于注释，但第一行#!也给程序指出本代码是靠/usr/bin/python执行的，所以文件名可以不是py
如果你乐意，你可以给helloworld.py 增加属性X，这样你可以把它改成任意的文件名直接执行，如hello。

#!/usr/bin/python
#filename:helloworld.py
print '\n\tHello World! That\'s Python!\n'
#if you want the .py file to be executable:chmod a+x helloworld.py

 案例2：

变量不用声明可以直接赋值；if/elif/else语句不用包括判断语句且以：结尾；

#!/usr/bin/python
#filename:raw_input.py

number = 23 #here no ; but you can add ; either
guess = int(raw_input("Enter an Integer:")); #string,can use ' or "

if guess == number: #notice: no () and there's a :
        print 'Congratulations, you guessed it.'
        print '(but you do not win any prizes!)'
elif guess < number:
        print "No, It's a little higher than what you input."
else:
        print 'No,It\'s a little lower than what you input.'

print "Done!";

 案例3：猜数字游戏，5次猜不对就退出

while循环，break跳出；省去了类似C语言的{}而改用对齐来决定语句块

#!/usr/bin/python
#filename:while.py

number = 23
Hitting = False
loop = 5

while not Hitting:
        guess = int(raw_input("Guess what(" + str(loop) +" times left):"))
        loop = loop -1 ;
        if loop == 0:
                print "\tToo stupid, you lost!"
                break;
        if guess > number :
                print "\tYour number is bigger than that."
        elif guess < number:
                print "\tYour number is littler than that."
        else:
                Hitting = True;
                print "\tYou WIN, Excellent Baby!"
print "\t--===--[DONE]--===--"
#the Done statement is line to while, so running out of while then "Done" execute.

 示例4：函数，默认参数，有返回值；DocString

#!/usr/bin/python
#filename:function.py

def value(num = 3): #there's default parameter.
        '''Coded by Phoenix :

        RET(X) = X^X''' #DocStrings
        ret = 1;
        for i in range(0,num): #notice, there is :
                ret = ret * num
        return ret

number = int(raw_input("Input a number:"))
print value()
print number**number
print value(number) #output the x^x, by the way, you can use: x**x
print value.__doc__ #output DocStrings