>>> a=random.randint(1,6,(5,3))>>> aarray([[5, 3, 1], [5, 5, 1], [5, 1, 3], [1, 4, 3], [5, 1, 2]])>>> b=a.tolist()>>> b#选取b列表的前2列[[5, 3, 1], [5, 5, 1], [5, 1, 3], [1, 4, 3], [5, 1, 2]]>>> c=mat(b)>>> cmatrix([[5, 3, 1], [5, 5, 1], [5, 1, 3], [1, 4, 3], [5, 1, 2]])>>> d=c[:,0:2]>>> d#将d转化回列表即可matrix([[5, 3], [5, 5], [5, 1], [1, 4], [5, 1]])
