python入门学习(四 Package以及数据类型)

Posted 2020-10-16 KvienChen

1,Python自带(build-in)package(主要用import导入)和外部(external)package

　　1.1自带package举例: os包;  os.getwd()

2.利用easy_install和pip 来安装扩展文件

　　2.1 例如 pip install request(s)

 

3.python 数据类型

　　3.1 总体上讲: numerics,sequesences,mappings,classes,instances,exceptions.

　　3.2 Numerics Types: int (包含Boolean),float,complex(复数行)

　　 int:unlimited length;

　　float 使用C的double实现利用sys.float_info;可以查看

　　complex: real(实部) imaginary(虚部) 分别用z.real和z.img来区分两部分

具体参见:https://docs.python.org/3/libary/stdtypes.html#numberic-types-int-float-complex

\'\'\'
Created on 201711

@author: Kevin
\'\'\'
import sys

a = 3
b = 4

c = 5.5
d = 6.5

e = complex(c,d)
f = complex(float(a),float(b))

print("a is type: ",type(a)) #type 是查看数据类型
print("a is type: ",type(c)) #type 是查看数据类型
print("a is type: ",type(e)) #type 是查看数据类型

print(a+b) #加
print(d/c) #除
print(b/a) #除
print(b//a) #两个除号四舍五入取整

print(e)
print(e+f)

print(sys.float_info)#float的具体信息

a is type:  <class \'int\'>
a is type:  <class \'float\'>
a is type:  <class \'complex\'>
7
1.1818181818181819
1.3333333333333333
1
(5.5+6.5j)
(8.5+10.5j)
sys.float_info(max=1.7976931348623157e+308, max_exp=1024, max_10_exp=308, min=2.2250738585072014e-308, min_exp=-1021, min_10_exp=-307, dig=15, mant_dig=53, epsilon=2.220446049250313e-16, radix=2, rounds=1)