numpy pandas 索引注意事项

pandas.DataFrame 的 iloc 

# ------------------------------------------------------------
'python式的切片，包含为尾位置'
In [23]:df = pd.DataFrame({
            'http_status': [200,200,404,404,301],
            'response_time': [0.04, 0.02, 0.07, 0.08, 1.0]},
            index=[0,1,2,3,4])

In [26]:df[1:3]
Out[26]: 
   http_status  response_time
1          200           0.02
2          404           0.07

In [24]:df.iloc[1:3,:]
Out[24]: 
   http_status  response_time
1          200           0.02
2          404           0.07


In [28]:df.values[1:3,:]
Out[28]: 
array([[  2.00000000e+02,   2.00000000e-02],
       [  4.04000000e+02,   7.00000000e-02]])

# ------------------------------------------------------------
'matlab式的切片，包含尾位置'
In [29]:df.ix[1:3,:]
Out[29]: 
   http_status  response_time
1          200           0.02
2          404           0.07
3          404           0.08