一、数据类型：
pc28源码搭建下载Q【115288oo99】
- 数值- 字符串- 列表- 元组- 字典
1.数值类型：
(1)整型
In [6]: a = 123
In [7]: type(a)
Out[7]: int
In [8]:
(2)长整型
In [8]: a = 199999999999999999999999999999
In [9]: a
Out[10]: 199999999999999999999999999999L
In [11]: type(a)
Out[12]: long
In [13]:
(3)浮点型
0.0, 12.0 -18.8 3e+7等
科学计数法是浮点型
In [11]: 3e+7
Out[11]: 30000000.0
In [12]: type(3e+7)
Out[12]: float
In [13]: 3.0/2
Out[13]: 1.5
In [14]: type(3.0/2)
Out[14]: float
In [15]:
(4)复数型
python对复数提供内嵌支持，这是大部分软件没有的。
In [8]: a = 3.14j
In [9]: a
Out[9]: 3.14j
In [10]: type(a)
Out[10]: complex
2.字符串类型：
In [12]: a = 'abc'
In [13]: a
Out[13]: 'abc'
In [14]: type(a)
Out[14]: str
In [15]:
三重引号还可以做注释：.
In [28]: a = 'hello\nworld'
In [29]: a
Out[29]: 'hello\nworld'
In [30]: a = "hello\nworld"
In [31]: a
Out[31]: 'hello\nworld'
In [39]: a = '''hello\nworld'''
In [40]: a
Out[40]: 'hello\nworld'
In [41]: print a
hello
world
In [42]:
In [43]: type(a)
Out[44]: str
序列索引：
In [42]: a = 'abcde'
In [43]: a[0]
Out[43]: 'a'
In [44]: a[1]
Out[44]: 'b'
In [45]: a[-1]
Out[45]: 'e'
In [46]: a[-2]
Out[46]: 'd'
序列切片：
In [42]: a = 'abcde'
In [43]: a[0]
Out[43]: 'a'
In [44]: a[1]
Out[44]: 'b'
In [45]: a[-1]
Out[45]: 'e'
In [46]: a[-2]
Out[46]: 'd'
In [47]: a[0:2]
Out[47]: 'ab'
In [48]: a[0:4]
Out[48]: 'abcd'
In [49]: a[0:3]
Out[49]: 'abc'
In [50]: a[1:3]
Out[50]: 'bc'
In [56]: a[0] + a[1]
Out[56]: 'ab'
In [57]: a[:2]
Out[57]: 'ab'
In [58]: a[:]
Out[58]: 'abcde'
In [59]: a[:-1]
Out[59]: 'abcd'
In [60]: a[::-1]
Out[60]: 'edcba'
In [61]: a[::1]
Out[61]: 'abcde'
In [62]: a[:3:1]
Out[62]: 'abc'
In [63]: a[::2]
Out[63]: 'ace'
In [64]: a
Out[64]: 'abcde'
In [65]: a[-4::-2]
Out[65]: 'b'
In [66]: a[-4:-2]
Out[66]: 'bc'
In [67]: a[-2:-4:-1]
Out[67]: 'dc'
In [68]: