placeholder传入值

placeholder译为占位符 通常为函数的输入值作占位符‘

feed_dict就是取代需要输入的值，将feed_dict的值placeholder的值 相当于一个输入值

import tensorflow as tf
input1=tf.placeholder(tf.float32)
input2=tf.placeholder(tf.float32)
#multiply(a,b) 是a与b的乘积
output=tf.multiply(input1,input2)
with tf.Session() as sess:
	print(sess.run(output,feed_dict={input1:[7.],input2:[2.]}))

输出

[14.]

参考  https://www.bilibili.com/video/av16001891/index_12.html?t=267#page=12