DataFrame 简介

面向 MATLAB 用户的 Python

Justin Kiggins

Product Manager

DataFrame

pandas 包
表格数据
pandas DataFrame = MATLAB 表
存储每条观测含混合类型的数据：
- 浮点数
- 整数
- 布尔值
- 字符串

DataFrame

                     rank num_households frac_dog_owners frac_cat_owners
state
Alabama              17   1828000        0.441           0.274          
Arizona              18   2515000        0.401           0.296          
Arkansas             6    1148000        0.479           0.306          
California           40   12974000       0.328           0.283          
Colorado             13   1986000        0.425           0.323          
Connecticut          33   1337000        0.283           0.319          
Delaware             25   334000         0.337           0.337          
District of Columbia 48   287000         0.131           0.116          
Florida              32   7609000        0.357           0.273          
Georgia              31   3798000        0.401           0.273

.head() 方法

pets.head()

            rank  num_households  frac_dog_owners  frac_cat_owners
state                                                             
Alabama       17         1828000            0.441            0.274
Arizona       18         2515000            0.401            0.296
Arkansas       6         1148000            0.479            0.306
California    40        12974000            0.328            0.283
Colorado      13         1986000            0.425            0.323

.columns 属性

pets.columns

Index(['rank', 'num_households', 'frac_dog_owners', 'frac_cat_owners'],
      dtype='object')

.index 属性

pets.index

Index(['Alabama', 'Arizona', 'Arkansas', 'California', 'Colorado',
       'Connecticut', 'Delaware', 'District of Columbia', 'Florida', 
       'Georgia', 'Idaho', 'Illinois', 'Indiana', 'Iowa', 'Kansas', 
       'Kentucky', 'Louisiana', 'Maine', 'Maryland', 'Massachusetts', 
       'Michigan', 'Minnesota', 'Mississippi', 'Missouri', 'Montana', 
       'Nebraska', 'Nevada', 'New Hampshire', 'New Jersey', 'New Mexico',
       'New York', 'North Carolina', 'North Dakota', 'Ohio', 'Oklahoma', 
       'Oregon', 'Pennsylvania', 'Rhode Island', 'South Carolina', 
       'South Dakota', 'Tennessee', 'Texas', 'Utah', 'Vermont', 'Virginia',
       'Washington', 'West Virginia', 'Wisconsin', 'Wyoming'],
      dtype='object', name='state')

提取单列

pets['rank']

state
Alabama                 17
Arizona                 18
Arkansas                 6
California              40
...
Virginia                37
Washington               5
West Virginia            7
Wisconsin               21
Wyoming                  9
Name: rank, dtype: int64

兼容 NumPy 与 Matplotlib

plt.scatter(pets['frac_dog_owners'], pets['frac_cat_owners'])

猫犬散点图

Vamos praticar!

面向 MATLAB 用户的 Python