 class="section level3">
<h3><span class="header-section-number">A.2.4</span> 堆叠辅助类：r_和c_</h3>
<p>NumPy命名空间中有两个特殊的对象——r_和c_，它们可以使数组的堆叠操作更为简洁：</p>
<pre><code>In [47]: arr = np.arange(6)

In [48]: arr1 = arr.reshape((3, 2))

In [49]: arr2 = np.random.randn(3, 2)

In [50]: np.r_[arr1, arr2]
Out[50]: 
array([[ 0.    ,  1.    ],
       [ 2.    ,  3.    ],
       [ 4.    ,  5.    ],
       [ 1.0072, -1.2962],
       [ 0.275 ,  0.228