tensorflow获取变量维度信息

# 直接获取TensorShape变量的第i个维度值
x.shape[i].value
x.get_shape()[i].value

# 将TensorShape变量转化为list类型，然后直接按照索引取值
x.get_shape().as_list()

import tensorflow as tf

x1 = tf.constant([[1,2,3],[4,5,6]])
# 占位符创建变量，第一个维度初始化为None，表示暂不指定维度
x2 = tf.placeholder(tf.float32,[None, 2,3])
print('x1.shape:',x1.shape)
print('x2.shape:',x2.shape)
print('x2.shape[1].value:',x2.shape[1].value)
print('tf.shape(x1):',tf.shape(x1))
print('tf.shape(x2):',tf.shape(x2))
print('x1.get_shape():',x1.get_shape())
print('x2.get_shape():',x2.get_shape())
print('x2.get_shape.as_list[1]:',x2.get_shape().as_list()[1])
shapeOP1 = tf.shape(x1)
shapeOP2 = tf.shape(x2)
with tf.Session() as sess:
 print('Within session, tf.shape(x1):',sess.run(shapeOP1))
 # 由于x2未进行完整的变量填充，其维度不完整，因此执行下面的命令将会报错
 # print('Within session, tf.shape(x2):',sess.run(shapeOP2)) # 此命令将会报错

x1.shape: (2, 3)
x2.shape: ("Shape:0", shape=(2,), dtype=int32)
tf.shape(x2): Tensor("Shape_1:0", shape=(3,), dtype=int32)
x1.get_shape(): (2, 3)
x2.get_shape(): (?, 2, 3)
x2.get_shape.as_list[1]: 2
Within session, tf.shape(x1): [2 3]