Python——数值类型

变量

[root@localhost mnt]# ipython
In [1]: a = 1

In [2]: type (a) ##整形
Out[2]: int

In [3]: aint = 111111111111111

In [4]: type(aint)
Out[4]: int

In [5]: along = 11111L

In [6]: type(along) ##长整形
Out[6]: long

In [7]: pi = 3.14

In [8]: type(pi) ##浮点型
Out[8]: float

In [9]: af = 1.2e10

In [11]: af
Out[11]: 12000000000.0

In [12]: type(af)
Out[12]: float

In [13]: abool = True
In [16]: type(abool)
Out[16]: bool

In [17]: acomplex = 1+1j ##复数

In [18]: type(acomplex)
Out[18]: complex

运算符和表达式

In [19]: a = 2

In [20]: b = 5

算数运算符

In [21]: a + b
Out[21]: 7

In [22]: a - b
Out[22]: -3

In [23]: a * b
Out[23]: 10

In [24]: b / a
Out[24]: 2

In [25]: a ** b
Out[25]: 32

In [26]: b // a
Out[26]: 2

In [27]: from future import division ##使用python3中的内容

In [28]: 5/2
Out[28]: 2.5

In [29]: 5//2
Out[29]: 2

In [30]: a = 1

赋值运算符

In [31]: a += 2

In [32]: a
Out[32]: 3

In [33]: a++
File “”, line 1
a++
^
SyntaxError: invalid syntax

In [34]: a = 3

In [35]: b = 1

关系运算符

In [36]: a > b
Out[36]: True

In [37]: a < b
Out[37]: False

In [38]: a != b
Out[38]: True

In [39]: a == b
Out[39]: False

逻辑运算符

In [40]: 1>2 and 2<3
Out[40]: False

In [41]: 1<2 and 2<3
Out[41]: True

In [42]: 1>2 or 2<3
Out[42]: True

In [43]: 1>2 or 2>3
Out[43]: False

In [45]: y = “h”

In [46]: not y
Out[46]: False

BIF ： built-in fuction (type,cmp,str) ##内置函数
In [1]: cmp(1,2)
Out[1]: -1

In [2]: cmp(2,2)
Out[2]: 0

In [3]: cmp(2,1)
Out[3]: 1

In [4]: abs(-10)
Out[4]: 10

In [6]: oct(8)
Out[6]: ‘010’

In [7]: hex(16)
Out[7]: ‘0x10’

In [8]: ord(‘a’)
Out[8]: 97

In [9]: chr(97)
Out[9]: ‘a’

输入与输出

In [17]: a = raw_input()
123

In [18]: a = raw_input(“A:”)
A:111

In [19]: a
Out[19]: ‘111’
In [20]: type(a)
Out[20]: str

In [21]: age = input(“A:”)
A:11

In [22]: type(age)
Out[22]: int

%d ##占位符，整形
%s ##字符串

In [23]: one = 10

In [24]: print “have :”,one
have : 10

In [25]: print “have:%d,A” %(one)
have:10,A

In [26]: two = ‘A’

In [27]: print “have:%d,two %s” %(one,two)
have:10,two A

In [28]: a = 1

In [29]: b = 1

In [30]: id(a)
Out[30]: 7711848

In [31]: id(b)
Out[31]: 7711848