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			95 lines
		
	
	
		
			3.8 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			95 lines
		
	
	
		
			3.8 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
| # -*- coding: utf-8 -*-
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| 
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| """
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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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| 
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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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| 
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| from qgis.core import (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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| from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
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| 
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| 
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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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| 
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|     def group(self):
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|         return self.tr('Vector selection')
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| 
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|     def groupId(self):
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|         return 'vectorselection'
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| 
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|     def __init__(self):
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|         super().__init__()
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| 
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|     def flags(self):
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|         return super().flags() | QgsProcessingAlgorithm.FlagNoThreading | QgsProcessingAlgorithm.FlagNotAvailableInStandaloneTool
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| 
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|     def initAlgorithm(self, config=None):
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|         self.methods = [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(QgsProcessingParameterVectorLayer(self.INPUT, self.tr('Input layer'), types=[QgsProcessing.TypeVector]))
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| 
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|         self.addParameter(QgsProcessingParameterExpression(self.EXPRESSION,
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|                                                            self.tr('Expression'), parentLayerParameterName=self.INPUT))
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|         self.addParameter(QgsProcessingParameterEnum(self.METHOD,
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|                                                      self.tr('Modify current selection by'), self.methods, defaultValue=0))
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| 
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|         self.addOutput(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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| 
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|     def displayName(self):
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|         return self.tr('Select by expression')
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| 
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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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| 
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|         method = self.parameterAsEnum(parameters, self.METHOD, context)
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|         if method == 0:
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|             behavior = QgsVectorLayer.SetSelection
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|         elif method == 1:
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|             behavior = QgsVectorLayer.AddToSelection
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|         elif method == 2:
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|             behavior = QgsVectorLayer.RemoveFromSelection
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|         elif method == 3:
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|             behavior = QgsVectorLayer.IntersectSelection
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| 
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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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| 
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|         layer.selectByExpression(expression, behavior)
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| 
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|         return {self.OUTPUT: parameters[self.INPUT]}
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