Python ProgrammingPython Programming

How to update the value of a variable in TensorFlow?

In order to update, increment and decrements the value of a variable, we use Variable.assign(), Variable.assign_add() and Variable.assign_sub() methods respectively.
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# TensorFlow program with example of variable assignment.

from __future__ import absolute_import
from __future__ import division
from __future__ import print_function

import tensorflow as tf

# Create a variable
variableA = tf.Variable(10, name="variableA")

# Start a session
sess = tf.Session()

# Initialization operation
init = tf.global_variables_initializer()

# Initialize variable
sess.run(init)

# Print session variable
print(sess.run(variableA))

# Assign new value to variable
sess.run(variableA.assign(20))
print(sess.run(variableA))

# Increment by 20
sess.run(variableA.assign_add(20))
print(sess.run(variableA))

# Decrement by 5
sess.run(variableA.assign_sub(5))
print(sess.run(variableA))

Sample output of above program.
C:\tf\examples\chapter6>pycodestyle --first example2.py

C:\tf\examples\chapter6>python example2.py
10
20
40
35

C:\tf\examples\chapter6>