http://sebug.net/paper/books/scipydoc/numpy_intro.html
npArr1=np.array([1,2,3],[4,5,6],[7,8,9]])
npArr1[0] #0th row
npArr1[0][1] #oth row ,1stcolumn
npArr1[:,0] #0column
>>> npArr2[0:2,1] #1th column, 0,1 row
array([2, 4])
原文：http://www.cnblogs.com/zyip/p/4196984.html