Source code for node_table_sort

# This file is part of Sympathy for Data.
# Copyright (c) 2013, Combine Control Systems AB
#
# Sympathy for Data is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, version 3 of the License.
#
# Sympathy for Data 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Sympathy for Data.  If not, see <http://www.gnu.org/licenses/>.
"""
In various programs, like file managers or spreadsheet programs, there do
often exist a functionality, where the data is sorted according to
some specified order of a specific part of the data. This functionality
do also exist in the standard library of Sympathy for Data and is represented
by the two nodes in this category.

The rows in the Tables are sorted according to the ascending/descending order
of a specified sort column. Both the sort column and the sort order have to
be specified in configuration GUI.
"""
from sympathy.api import node as synode
from sympathy.api import node_helper
from sympathy.api.nodeconfig import Tag, Tags, adjust, Port, Ports
from sympathy.api.exceptions import SyDataError
import numpy as np


def _get_single_col_editor():
    return synode.Util.combo_editor('', filter=True, edit=True)


class SortRowsTable(synode.Node):
    """
    Sort table rows according to ascending/descending order of a sort
    column.
    """

    author = 'Greger Cronquist'
    version = '1.1'
    icon = 'sort_table_rows.svg'
    tags = Tags(Tag.DataProcessing.TransformStructure)

    name = 'Sort rows in Table'
    nodeid = 'org.sysess.sympathy.data.table.sorttable'

    inputs = Ports([Port.Table('Input', name='Input')])
    outputs = Ports([Port.Table('Input', name='Output')])

    editor = _get_single_col_editor()
    parameters = synode.parameters()
    parameters.set_list(
        'column', label='Sort column',
        description='Column to sort',
        editor=editor)
    parameters.set_list(
        'sort_order', label='Sort order',
        list=['Ascending', 'Descending'], value=[0],
        description='Sort order',
        editor=synode.Util.combo_editor().value())

    def update_parameters(self, old_params):
        param = 'column'
        if param in old_params:
            old_params[param].editor = _get_single_col_editor()

    def adjust_parameters(self, node_context):
        adjust(node_context.parameters['column'], node_context.input['Input'])

    def execute(self, node_context):
        in_table = node_context.input['Input']
        out_table = node_context.output['Output']
        parameters = node_context.parameters

        if in_table.is_empty():
            return

        column_param = parameters['column']
        column = in_table._require_column(column_param)
        idx = np.ma.argsort(column, kind='mergesort')
        if parameters['sort_order'].selected == 'Descending':
            idx = idx[::-1]

        if isinstance(column, np.ma.MaskedArray):
            masked = np.ma.getmaskarray(column)[idx]
            if parameters['sort_order'].selected == 'Ascending':
                # Ascending: put masked values last
                idx = np.concatenate((idx[~masked], idx[masked]))
            else:
                # Descending: put masked values first
                idx = np.concatenate((idx[masked], idx[~masked]))

        for column_name in in_table.column_names():
            array = in_table.get_column_to_array(column_name)
            out_table.set_column_from_array(column_name, array[idx])

        out_table.set_attributes(in_table.get_attributes())
        out_table.set_name(in_table.get_name())


@node_helper.list_node_decorator(['Input'], ['Output'])
class SortRowsTables(SortRowsTable):
    name = 'Sort rows in Tables'
    nodeid = 'org.sysess.sympathy.data.table.sorttables'