Python 有点意思

基本语法

>>> width = 20

>>> height = 2 * 3

>>> width * height

120

>>> x = y = z = 0

>>> x

0

>>> y

0

>>> z

0

变量在使用前，必须定义

>>> n

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

NameError: name 'n' is not defined

对浮点数支持很好

>>> 7.0 / 2

3.5

>>> 7 / 2

3

>>> hello = "This is a string\n Hello Python."

>>> print hello

This is a string

 Hello Python.

>>> hello

'This is a string\n Hello Python.'

print 可以输出内容。

字符串可以由 + 操作符连接（粘到一起），可以由 * 重复。

>>> word = 'Help' + 'A'

>>> word

'HelpA'

>>> word * 5

'HelpAHelpAHelpAHelpAHelpA'

这个厉害了。

>>> word[4]

'A'

>>> word[0:2]

'He'

>>> word[2:4]

'lp'

>>> word[:2]

'He'

>>> word[2:]

'lpA'

>>> word[1:100]

'elpA'

>>> word[10:0]

''

>>> word[2:1]

''

>>> word[-1]

'A'

>>> word[-2]

'p'

>>> word[-2:]

'pA'

>>> word[:-2]

'Hel'

 +---+---+---+---+---+

 | H | e | l | p | A |

 +---+---+---+---+---+

 0   1   2   3   4

-5  -4  -3  -2  -1

>>> s = "hello world"

>>> len(s)

11

>>> u'Hello\u0020World !'

u'Hello World !'

转码序列 \u0020 表示在指定位置插入编码为 0x0020 的 Unicode 字符（空格）。

>>> h = u'Hello\u0020World !'

>>> print h

Hello World !

>>> h

u'Hello World !'

列表

>>> a = ['hello','world',100,20]

>>> a

['hello', 'world', 100, 20]

>>> len(a)

4

>>> a[0]

'hello'

>>> a[3]

20

>>> a[0:2] + ['python',2*2]

['hello', 'world', 'python', 4]

编程

>>> a,b = 0,1

>>> a

0

>>> b

1

>>> while b < 10:

...     print b

...     a,b = b,a+b

...

1

1

2

3

5

8

>>> i = 2 * 2

>>> print 'The value of i is',i

The value of i is 4

学习给我快乐，没有别的目的。