Tensorflow 基础知识（二）——四则运算

import tensorflow as tf
data1 = tf.constant(6)
data2 = tf.constant(2)
dataAdd = tf.add(data1,data2)      # 加法
dataMul = tf.multiply(data1,data2) # 乘法
dataSub = tf.subtract(data1,data2) # 减法
dataDiv = tf.divide(data1,data2)   # 除法
with tf.Session() as sess:
    print(sess.run(dataAdd))
    print(sess.run(dataMul))
    print(sess.run(dataSub))
    print(sess.run(dataDiv))
print('end!')

输出： 

8
12
4
3.0
end!

import tensorflow as tf
data1 = tf.constant(6)
data2 = tf.Variable(2)
dataAdd = tf.add(data1,data2)
dataCopy = tf.assign(data2,dataAdd) # dataAdd -> data2
dataMul = tf.multiply(data1,data2)
dataSub = tf.subtract(data1,data2)
dataDiv = tf.divide(data1,data2)

init = tf.global_variables_initializer()
with tf.Session() as sess:
    sess.run(init)
    print(sess.run(dataAdd))
    print(sess.run(dataMul))
    print(sess.run(dataSub))
    print(sess.run(dataDiv))
    print('sess.run(dataCopy)',sess.run(dataCopy)) # 8->data
    print('dataCopy.eval()',dataCopy.eval()) # 8+6->14->data=14    获取默认session 
    print('tf.get_default_session()',tf.get_default_session().run(dataCopy)) # 14+6->20->data=20
print('end!')

 输出：

8
12
4
3.0
sess.run(dataCopy) 8
dataCopy.eval() 14
tf.get_default_session() 20
end!