64 lines
2.1 KiB
Python
64 lines
2.1 KiB
Python
"""\
|
|
@file iterators.py
|
|
@brief Useful general-purpose iterators.
|
|
|
|
$LicenseInfo:firstyear=2008&license=mit$
|
|
|
|
Copyright (c) 2008-2009, Linden Research, Inc.
|
|
|
|
Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
of this software and associated documentation files (the "Software"), to deal
|
|
in the Software without restriction, including without limitation the rights
|
|
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|
copies of the Software, and to permit persons to whom the Software is
|
|
furnished to do so, subject to the following conditions:
|
|
|
|
The above copyright notice and this permission notice shall be included in
|
|
all copies or substantial portions of the Software.
|
|
|
|
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
|
|
THE SOFTWARE.
|
|
$/LicenseInfo$
|
|
"""
|
|
|
|
from __future__ import nested_scopes
|
|
|
|
def iter_chunks(rows, aggregate_size=100):
|
|
"""
|
|
Given an iterable set of items (@p rows), produces lists of up to @p
|
|
aggregate_size items at a time, for example:
|
|
|
|
iter_chunks([1,2,3,4,5,6,7,8,9,10], 3)
|
|
|
|
Values for @p aggregate_size < 1 will raise ValueError.
|
|
|
|
Will return a generator that produces, in the following order:
|
|
- [1, 2, 3]
|
|
- [4, 5, 6]
|
|
- [7, 8, 9]
|
|
- [10]
|
|
"""
|
|
if aggregate_size < 1:
|
|
raise ValueError()
|
|
|
|
def iter_chunks_inner():
|
|
row_iter = iter(rows)
|
|
done = False
|
|
agg = []
|
|
while not done:
|
|
try:
|
|
row = row_iter.next()
|
|
agg.append(row)
|
|
except StopIteration:
|
|
done = True
|
|
if agg and (len(agg) >= aggregate_size or done):
|
|
yield agg
|
|
agg = []
|
|
|
|
return iter_chunks_inner()
|