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125 lines
4.1 KiB
Python
125 lines
4.1 KiB
Python
"""
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***************************************************************************
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SelectByExpression.py
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---------------------
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Date : July 2014
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Copyright : (C) 2014 by Michael Douchin
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***************************************************************************
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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***************************************************************************
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"""
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__author__ = "Michael Douchin"
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__date__ = "July 2014"
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__copyright__ = "(C) 2014, Michael Douchin"
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from qgis.core import (
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QgsExpression,
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QgsProcessing,
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QgsVectorLayer,
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QgsProcessingAlgorithm,
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QgsProcessingException,
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QgsProcessingParameterVectorLayer,
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QgsProcessingParameterExpression,
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QgsProcessingParameterEnum,
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QgsProcessingOutputVectorLayer,
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)
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from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
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class SelectByExpression(QgisAlgorithm):
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INPUT = "INPUT"
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EXPRESSION = "EXPRESSION"
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OUTPUT = "OUTPUT"
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METHOD = "METHOD"
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def group(self):
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return self.tr("Vector selection")
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def groupId(self):
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return "vectorselection"
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def __init__(self):
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super().__init__()
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def flags(self):
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return (
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super().flags()
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| QgsProcessingAlgorithm.Flag.FlagNoThreading
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| QgsProcessingAlgorithm.Flag.FlagNotAvailableInStandaloneTool
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)
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def initAlgorithm(self, config=None):
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self.methods = [
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self.tr("creating new selection"),
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self.tr("adding to current selection"),
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self.tr("removing from current selection"),
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self.tr("selecting within current selection"),
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]
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self.addParameter(
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QgsProcessingParameterVectorLayer(
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self.INPUT,
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self.tr("Input layer"),
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types=[QgsProcessing.SourceType.TypeVector],
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)
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)
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self.addParameter(
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QgsProcessingParameterExpression(
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self.EXPRESSION,
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self.tr("Expression"),
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parentLayerParameterName=self.INPUT,
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)
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)
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self.addParameter(
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QgsProcessingParameterEnum(
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self.METHOD,
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self.tr("Modify current selection by"),
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self.methods,
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defaultValue=0,
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)
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)
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self.addOutput(
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QgsProcessingOutputVectorLayer(self.OUTPUT, self.tr("Selected (attribute)"))
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)
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def name(self):
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return "selectbyexpression"
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def displayName(self):
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return self.tr("Select by expression")
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def shortDescription(self):
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return self.tr("Creates a selection in a vector layer based on a QGIS expression.")
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def processAlgorithm(self, parameters, context, feedback):
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layer = self.parameterAsVectorLayer(parameters, self.INPUT, context)
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method = self.parameterAsEnum(parameters, self.METHOD, context)
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if method == 0:
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behavior = QgsVectorLayer.SelectBehavior.SetSelection
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elif method == 1:
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behavior = QgsVectorLayer.SelectBehavior.AddToSelection
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elif method == 2:
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behavior = QgsVectorLayer.SelectBehavior.RemoveFromSelection
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elif method == 3:
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behavior = QgsVectorLayer.SelectBehavior.IntersectSelection
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expression = self.parameterAsString(parameters, self.EXPRESSION, context)
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qExp = QgsExpression(expression)
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if qExp.hasParserError():
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raise QgsProcessingException(qExp.parserErrorString())
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expression_context = self.createExpressionContext(parameters, context)
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layer.selectByExpression(expression, behavior, expression_context)
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return {self.OUTPUT: parameters[self.INPUT]}
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