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[processing] added 'Select by expression' algorithm (by Michaël Douch…
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# -*- coding: utf-8 -*- | ||
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""" | ||
*************************************************************************** | ||
SelectByExpression.py | ||
--------------------- | ||
Date : July 2014 | ||
Copyright : (C) 2014 by Michaël Douchin | ||
*************************************************************************** | ||
* * | ||
* This program 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; either version 2 of the License, or * | ||
* (at your option) any later version. * | ||
* * | ||
*************************************************************************** | ||
""" | ||
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__author__ = 'Michael Douchin' | ||
__date__ = 'July 2014' | ||
__copyright__ = '(C) 2014, Michael Douchin' | ||
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# This will get replaced with a git SHA1 when you do a git archive | ||
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__revision__ = '$Format:%H$' | ||
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import processing | ||
from qgis.core import * | ||
from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException | ||
from processing.parameters.ParameterVector import ParameterVector | ||
from processing.parameters.ParameterSelection import ParameterSelection | ||
from processing.outputs.OutputVector import OutputVector | ||
from processing.core.GeoAlgorithm import GeoAlgorithm | ||
from processing.parameters.ParameterString import ParameterString | ||
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class SelectByExpression(GeoAlgorithm): | ||
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LAYERNAME = 'LAYERNAME' | ||
EXPRESSION= 'EXPRESSION' | ||
RESULT = 'RESULT' | ||
METHOD = 'METHOD' | ||
METHODS = ['creating new selection', 'adding to current selection', | ||
'removing from current selection'] | ||
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def defineCharacteristics(self): | ||
self.name = 'Select by expression' | ||
self.group = 'Vector selection tools' | ||
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self.addParameter(ParameterVector(self.LAYERNAME, 'Input Layer', | ||
[ParameterVector.VECTOR_TYPE_ANY])) | ||
self.addParameter(ParameterString(self.EXPRESSION, "Expression")) | ||
self.addParameter(ParameterSelection(self.METHOD, | ||
'Modify current selection by', self.METHODS, 0)) | ||
self.addOutput(OutputVector(self.RESULT, 'Output', True)) | ||
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def processAlgorithm(self, progress): | ||
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filename = self.getParameterValue(self.LAYERNAME) | ||
layer = processing.getObject(filename) | ||
oldSelection = set(layer.selectedFeaturesIds()) | ||
method = self.getParameterValue(self.METHOD) | ||
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# Build QGIS request with expression | ||
expression = self.getParameterValue(self.EXPRESSION) | ||
qExp = QgsExpression(expression) | ||
if not qExp.hasParserError(): | ||
qReq = QgsFeatureRequest(qExp) | ||
else: | ||
raise GeoAlgorithmExecutionException(qExp.parserErrorString()) | ||
selected = [f.id() for f in layer.getFeatures(qReq)] | ||
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if method == 1: | ||
selected = list(oldSelection.union(selected)) | ||
elif method == 2: | ||
selected = list(oldSelection.difference(selected)) | ||
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# Set the selection | ||
layer.setSelectedFeatures(selected) | ||
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self.setOutputValue(self.RESULT, filename) |