tensorflow

tf.count_up_to(ref, limit, name=None)
Increments 'ref' until it reaches 'limit'.
This operation outputs "ref" after the update is done. This makes it easier to chain operations that need to use the updated value.

Args:

ref: A mutable Tensor. Must be one of the following types: int32, int64. Should be from a scalar Variable node.
limit: An int. If incrementing ref would bring it above limit, instead generates an 'OutOfRange' error.
name: A name for the operation (optional).
Returns:

A Tensor. Has the same type as ref. A copy of the input before increment. If nothing else modifies the input, the values produced will all be distinct.

代码示例：

import tensorflow as tf
with tf.Session().as_default():
  var = tf.Variable(0)
  count = var.count_up_to(3)
  tf.initialize_all_variables().run()
  print(var.eval())
  print(count.eval())
  print(var.eval())

输出：0、0、1