# Copyright (C) 2009-2019 Martin Slouf <martinslouf@users.sourceforge.net>
#
# This file is a part of Summer.
#
# Summer is free software; you can redistribute it and/or modify it under
# the terms of the GNU Lesser General Public License as published by the Free
# Software Foundation; either version 3 of the License, or (at your option)
# any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
"""List of dictionaries (*lod*) -- simple yet powerfull in memory data
structure, ie. *grid*.
Thanks to: http://stackoverflow.com/questions/1038160/python-data-structure-for-maintaing-tabular-data-in-memory
This module is not imported into public *summer* namespace, so you should
import it directly::
from summer import lod
"""
import csv
import logging
import io
logger = logging.getLogger(__name__)
[docs]def lod_populate(lod: list, fin: io.IOBase):
"""Populate lod using CSV file.
Args:
lod (list): list to be extended with data
fin (io.IOBase): file-like object in CSV format
"""
rdr = csv.DictReader(fin, delimiter=";", quotechar='"')
lod.extend(rdr)
[docs]def lod_query(lod: list, filter_obj=None, sort_keys=None):
"""Lookup in lod based on query.
Args:
lod (list): lod to be used
filter_obj: filter to be used
sort_keys: sort criteria
Returns:
list: collection of matching rows
"""
if filter_obj is not None:
tmp = (r for r in lod if list(filter_obj(r)))
if sort_keys is not None:
tmp = sorted(lod, key=lambda r: [r[k] for k in sort_keys])
else:
tmp = list(lod)
return tmp
[docs]def lod_lookup(lod: list, **kw):
"""Lookup in lod by attribute values.
Args:
lod (list): lod to be used
**kw (dict): use keyword arguments. keys are column names, their
value is attribute value
Returns:
list: first matching row
"""
for row in lod:
for k, v in kw.items():
if row[k] != str(v):
break
else:
return row
return None