numpy&pandas补充常用示例

In [115]: a = np.arange(12).reshape((3,4))                                                                                                                                                        

In [116]: a                                                                                                                                                                                       
Out[116]: 
array([[ 0,  1,  2,  3],
       [ 4,  5,  6,  7],
       [ 8,  9, 10, 11]])

In [117]: a[1:,1:3]                                                                                                                                                                               
Out[117]: 
array([[ 5,  6],
       [ 9, 10]])

In [118]:
In [115]: a = np.arange(12)