QGIS » QGIS Application

# -*- coding: utf-8 -*-

"""

/***************************************************************************

 TlugProcessing

                                 Find duplicates

 TLUG Algorithms

                              -------------------

        begin                : 2017-10-25

        copyright            : (C) 2017 by Thüringer Landesanstalt für Umwelt und Geologie (TLUG)

        email                : [email protected]

 ***************************************************************************/

/***************************************************************************

 *                                                                         *

 *   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.                                   *

 *                                                                         *

 ***************************************************************************/

"""

__author__ = 'Michael Kürbs'

__date__ = '2018-07-31'

__copyright__ = '(C) 2017 Michael Kürbs by Thüringer Landesanstalt für Umwelt und Geologie (TLUG)'

# This will get replaced with a git SHA1 when you do a git archive

__revision__ = '$Format:%H$'

from qgis.core import (QgsExpression,

                       QgsProcessing,

                       QgsExpressionContext,

                       QgsExpressionContextScope,

                       QgsVectorLayer,

                       QgsProcessingAlgorithm,

                       QgsProcessingException,

                       QgsProcessingParameterVectorLayer,

                       QgsProcessingParameterExpression,

                       QgsProcessingParameterEnum,

                       QgsProcessingOutputVectorLayer)

from PyQt5.QtCore import QCoreApplication

from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm

class FindDuplicates(QgisAlgorithm):#QgsProcessingAlgorithm):

    """

    This is an algorithm that selects all duplicates in a table field.

    """

    INPUT = 'INPUT'

    EXPRESSION = 'EXPRESSION'

    OUTPUT = 'OUTPUT'

    def initAlgorithm(self, config):

        """

        Here we define the inputs and output of the algorithm, along

        with some other properties.

        """

        self.addParameter(QgsProcessingParameterVectorLayer(self.INPUT, self.tr('Input layer'), types=[QgsProcessing.TypeVector]))

        self.addParameter(QgsProcessingParameterExpression(self.EXPRESSION,

                                                           self.tr('Expression'), parentLayerParameterName=self.INPUT))

        self.addOutput(QgsProcessingOutputVectorLayer(self.OUTPUT, self.tr('Selected (attribute)')))

    def processAlgorithm(self, parameters, context, feedback):

        """

        Here is where the processing itself takes place.

        """

        vectorLayer= self.parameterAsVectorLayer(parameters, self.INPUT, context)

        expression = self.parameterAsString(parameters, self.EXPRESSION, context)

        expr=QgsExpression(expression)

        if expr.hasParserError():

            raise QgsProcessingException(expr.parserErrorString())

        context = QgsExpressionContext()

        scope = QgsExpressionContextScope()

        count = vectorLayer.featureCount() if vectorLayer.featureCount() else 0

        total = 100.0 / count

        # And now we can process

        attributes=[]

        duplicates=[]

        index=0

        protokoll=[]

        #Iterating over Vector Layer

        iter = vectorLayer.getFeatures()

        for current, feature in enumerate(iter):

            try:

                #create value from Expression

                scope.setFeature(feature)

                context.appendScope(scope)

                value=expr.evaluate(context)

            except:

                msg="Error while run Expression" + str( expr.expression() ) + " on feature " + str( feature.attributes() ) 

                feedback.reportError(msg)

                raise QgsProcessingException(msg)

            try:

                #is the attribut in the list yet

                index=attributes.index(value)

                #index=attributes.index(feature[fidx])

            except ValueError: # value is not in the list

                index = -1

            except KeyError: # value is not in the list

                index = -1

            protokoll.append([str(value), "-->", str(index)])

            if index == -1: # add new attribute in the list

                attributes.append(value)

            else: # it is a duplicate

                duplicates.append(feature.id())

                feedback.pushInfo( str(feature.id()) + " added")

            # Update the progress bar

            proz=int( current+1 * total)

            feedback.pushInfo( str( value ) +  " Index: " + str( index ) + " " + str(proz) + "%")

            feedback.setProgress( proz )

        if len( duplicates ) > 0:

            vectorLayer.select(duplicates)

        for item in protokoll:

            feedback.pushInfo( str( item ) ) 

        return {self.OUTPUT: parameters[self.INPUT]}

    def name(self):

        return 'FinddDuplicates'

    def displayName(self):

        return self.tr('Find Duplicates')

    def group(self):

        return self.tr('Vector selection')

    def groupId(self):

        return 'vectorselection'

    def __init__(self):

        super().__init__()

    def flags(self):

        return super().flags() | QgsProcessingAlgorithm.FlagNoThreading

    def metadata(self):

        return self.tr('TLUG:Find Duplicates, Select duplicate values in a feature field.')

    def description(self):

        return self.tr('Processing', 'Select duplicate values in a feature field.')

    def tr(self, string):

        return QCoreApplication.translate('Processing', string)

    def createInstance(self):

        return FindDuplicates()