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Paddle/python/paddle/batch.py

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2.2 KiB

# Copyright (c) 2016 PaddlePaddle Authors. All Rights Reserved
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
__all__ = ['batch']
def batch(reader, batch_size, drop_last=False):
"""
This operator creates a batched reader which combines the data from the
input reader to batched data.
Args:
reader(generator): the data reader to read from.
batch_size(int): size of each mini-batch.
drop_last(bool, optional): If set to True, the last batch is dropped when
the size of last batch is not equal to batch_size, if set to False,
it will not. Default: False.
Returns:
The batched reader.
Return Type:
generator
Examples:
.. code-block:: python
import paddle.fluid as fluid
def reader():
for i in range(10):
yield i
batch_reader = fluid.io.batch(reader, batch_size=2)
for data in batch_reader():
print(data)
# Output is
# [0, 1]
# [2, 3]
# [4, 5]
# [6, 7]
# [8, 9]
"""
def batch_reader():
r = reader()
b = []
for instance in r:
b.append(instance)
if len(b) == batch_size:
yield b
b = []
if drop_last == False and len(b) != 0:
yield b
# Batch size check
batch_size = int(batch_size)
if batch_size <= 0:
raise ValueError("batch_size should be a positive integeral value, "
"but got batch_size={}".format(batch_size))
return batch_reader