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			107 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			107 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
| # -*- coding: utf-8 -*-
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| 
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| """
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| ***************************************************************************
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|     DeleteColumn.py
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|     ---------------------
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|     Date                 : May 2010
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|     Copyright            : (C) 2010 by Michael Minn
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|     Email                : pyqgis at michaelminn dot com
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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 Minn'
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| __date__ = 'May 2010'
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| __copyright__ = '(C) 2010, Michael Minn'
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| 
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| from qgis.PyQt.QtCore import QCoreApplication
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| 
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| from qgis.core import (QgsProcessingParameterField,
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|                        QgsProcessing,
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|                        QgsProcessingAlgorithm,
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|                        QgsProcessingFeatureSource)
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| from processing.algs.qgis.QgisAlgorithm import QgisFeatureBasedAlgorithm
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| 
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| 
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| class DeleteColumn(QgisFeatureBasedAlgorithm):
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| 
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|     COLUMNS = 'COLUMN'
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| 
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|     def flags(self):
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|         return super().flags() & ~QgsProcessingAlgorithm.FlagSupportsInPlaceEdits
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| 
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|     def tags(self):
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|         return self.tr('drop,delete,remove,fields,columns,attributes').split(',')
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| 
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|     def group(self):
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|         return self.tr('Vector table')
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| 
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|     def groupId(self):
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|         return 'vectortable'
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| 
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|     def __init__(self):
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|         super().__init__()
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|         self.fields_to_delete = []
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|         self.field_indices = []
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| 
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|     def initParameters(self, config=None):
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|         self.addParameter(QgsProcessingParameterField(self.COLUMNS,
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|                                                       self.tr('Fields to drop'),
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|                                                       None, 'INPUT', QgsProcessingParameterField.Any, True))
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| 
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|     def inputLayerTypes(self):
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|         return [QgsProcessing.TypeVector]
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| 
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|     def name(self):
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|         return 'deletecolumn'
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| 
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|     def displayName(self):
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|         return self.tr('Drop field(s)')
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| 
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|     def outputName(self):
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|         return self.tr('Remaining fields')
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| 
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|     def prepareAlgorithm(self, parameters, context, feedback):
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|         self.fields_to_delete = self.parameterAsFields(parameters, self.COLUMNS, context)
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| 
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|         source = self.parameterAsSource(parameters, 'INPUT', context)
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|         if source is not None:
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|             for f in self.fields_to_delete:
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|                 index = source.fields().lookupField(f)
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|                 if index < 0:
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|                     feedback.pushInfo(QCoreApplication.translate('DeleteColumn', 'Field “{}” does not exist in input layer').format(f))
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| 
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|         return super().prepareAlgorithm(parameters, context, feedback)
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| 
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|     def outputFields(self, input_fields):
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|         # loop through twice - first we need to build up a list of original attribute indices
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|         for f in self.fields_to_delete:
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|             index = input_fields.lookupField(f)
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|             if index >= 0:
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|                 self.field_indices.append(index)
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| 
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|         # important - make sure we remove from the end so we aren't changing used indices as we go
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|         self.field_indices.sort(reverse=True)
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| 
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|         # this second time we make a cleaned version of the fields
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|         for index in self.field_indices:
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|             input_fields.remove(index)
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|         return input_fields
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| 
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|     def sourceFlags(self):
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|         return QgsProcessingFeatureSource.FlagSkipGeometryValidityChecks
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| 
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|     def processFeature(self, feature, context, feedback):
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|         attributes = feature.attributes()
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|         for index in self.field_indices:
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|             del attributes[index]
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|         feature.setAttributes(attributes)
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|         return [feature]
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