import tensorflow as tf

 a = tf.constant([1,2,3])

 b = tf.constant([4,5,6])

 c1 = tf.stack([a,b],axis=0)

 c2 = tf.stack([a,b],axis=1)

 #take c2 for example showing results of unstack

 d1 = tf.unstack(c2,axis=0) # Return: The list of Tensor objects unstacked from value.

 d2 = tf.unstack(c2,axis=1)

 with tf.Session() as sess:

     print('c1(with shape:{}):\n{}'.format(c1.shape, sess.run(c1)))

     print('c2(with shape:{}):\n{}'.format(c2.shape, sess.run(c2)))

     print('d1(with length:{}):\n{}'.format(len(d1), sess.run(d1)))

     print('d2(with length:{}):\n{}'.format(len(d2), sess.run(d2)))