转自 http://www.cnblogs.com/BeginMan/archive/2013/06/08/3125876.html
一、标准类型函数
cmp():比较大小
str():转换为字符串
type():类型
cmp
(...)
cmp
(x, y)
-
> integer
Return negative(负数)
if
x<y, zero(
0
)
if
x
=
=
y, positive(正数)
if
x>y.
|
如下:
>>>
cmp
(
5
,
3.2
)
1
>>>
cmp
(
3.5
,
8
)
-
1
|
二、转换工厂函数
存在精度损失
>>>
int
(
1.847
)
1
>>>
long
(
42
)
42L
>>>
float
(
42
)
42.0
>>>
complex
(
42
)
(
42
+
0j
)
>>>
complex
(
2.4
,
-
8
)
(
2.3999999999999999
-
8j
)
|
三、功能函数
用于数值运算:asb()、coerce()、divmod()、pow()、round()
asb():absolute:绝对的;完全的;专制的;n:绝对值
>>>
abs
(
-
1
)
1
|
coerce():vt. 强制,迫使,
类型转换,但是提供了不依赖python解释器而是通过自定义两个数值类型转换。返回一个元祖,存在强制行为。
coerce(...)
coerce(x, y) -> (x1, y1)
Return a tuple consisting of the two numeric arguments converted to
a common type, using the same rules as used by arithmetic operations.
If coercion is not possible, raise TypeError.
>>>
coerce
(
1
,
2
)
(
1
,
2
)
>>>
coerce
(
1.2
,
2l
)
(
1.2
,
2.0
)
>>>
coerce
(
1.2
,
2
)
(
1.2
,
2.0
)
>>>
coerce
(
1
,
2.3
)
(
1.0
,
2.2999999999999998
)
>>>
coerce
(
1j
,
123
)
(
1j
, (
123
+
0j
))
|
divmod():.divmod 整除求余、返回包含商和余数的元祖
>>>
divmod
(
10
,
3
)
(
3
,
1
)
>>>
divmod
(
3
,
10
)
(
0
,
3
)
>>>
divmod
(
10
,
2.5
)
(
4.0
,
0.0
)
|
pow():power of a number:指数的意思
pow()与**都可以实现指数运算,pow()先出生些。
>>>
pow
(
2
,
5
)
32
>>>
2
*
*
5
32
|
round():四舍五入
round(...)
round(number[, ndigits]) -> floating point number
Round a number to a given precision in decimal digits (default 0 digits).
This always returns a floating point number. Precision may be negative.
>>>
round
(
1.234
,
2
)
1.23
>>>
round
(
3.14
)
3.0
>>>
for
each
in
range
(
10
):
print
round
(math.pi,each)
3.0
3.1
3.14
3.142
3.1416
3.14159
3.141593
3.1415927
3.14159265
3.141592654
|
四、仅用于整数的函数
oct():octonary number system 八进制字符串形式
>>>
oct
(
255
)
'0377'
|
hex():hexadecimal number system十六进制字符串形式
>>>
hex
(
255
)
'0xff'
|
ASCII码转换函数
ord():ordinal:序数,将字符转换成对应整数值
>>>
ord
(
'A'
)
65
|
chr():char: 单个字符,数字对应当个ASCII字符
>>>
chr
(
65
)
'A'
|
五、操作符
>>> x>
=
80
and
x<
=
100
True
>>>
80
<
=
x<
=
100
True
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
总是写错:
>>>
80
=
|
六、致用
1、分数等级
def
result(x):
dic
=
{
9
:
'A'
,
8
:
'B'
,
7
:
'C'
,
6
:
'D'
}
myre
=int(
x)
/
10
for
obj
in
sorted
(dic.keys(),reverse
=
True
): #True 和False 表示是否逆序
if
myre>
=
obj:
out
=
dic[obj]
break
else
:
out
=
'F'
return
out
if
__name__
=
=
"__main__"
:
sorce
=
input
(
'Enter your sorce:'
)
print
'level:%s'
%
result(sorce)