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139 lines
5.4 KiB
Python
139 lines
5.4 KiB
Python
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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SelectByAttribute.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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__author__ = 'Michael Minn'
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__date__ = 'May 2010'
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__copyright__ = '(C) 2010, Michael Minn'
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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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from qgis.PyQt.QtCore import QVariant
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from qgis.core import (QgsExpression,
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QgsProcessingException,
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QgsProcessingParameterVectorLayer,
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QgsProcessingParameterField,
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QgsProcessingParameterEnum,
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QgsProcessingParameterString,
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QgsProcessingOutputVectorLayer)
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from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
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class SelectByAttribute(QgisAlgorithm):
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INPUT = 'INPUT'
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FIELD = 'FIELD'
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OPERATOR = 'OPERATOR'
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VALUE = 'VALUE'
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OUTPUT = 'OUTPUT'
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OPERATORS = ['=',
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'!=',
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'>',
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'>=',
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'<',
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'<=',
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'begins with',
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'contains',
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'is null',
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'is not null',
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'does not contain'
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]
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STRING_OPERATORS = ['begins with',
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'contains',
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'does not contain']
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def tags(self):
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return self.tr('select,attribute,value,contains,null,field').split(',')
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def group(self):
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return self.tr('Vector selection')
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def __init__(self):
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super().__init__()
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def initAlgorithm(self, config=None):
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self.i18n_operators = ['=',
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'!=',
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'>',
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'>=',
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'<',
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'<=',
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self.tr('begins with'),
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self.tr('contains'),
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self.tr('is null'),
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self.tr('is not null'),
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self.tr('does not contain')
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]
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self.addParameter(QgsProcessingParameterVectorLayer(self.INPUT, self.tr('Input layer')))
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self.addParameter(QgsProcessingParameterField(self.FIELD,
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self.tr('Selection attribute'), parentLayerParameterName=self.INPUT))
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self.addParameter(QgsProcessingParameterEnum(self.OPERATOR,
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self.tr('Operator'), self.i18n_operators))
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self.addParameter(QgsProcessingParameterString(self.VALUE, self.tr('Value')))
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self.addOutput(QgsProcessingOutputVectorLayer(self.OUTPUT, self.tr('Selected (attribute)')))
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def name(self):
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return 'selectbyattribute'
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def displayName(self):
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return self.tr('Select by attribute')
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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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fieldName = self.parameterAsString(parameters, self.FIELD, context)
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operator = self.OPERATORS[self.parameterAsEnum(parameters, self.OPERATOR, context)]
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value = self.parameterAsString(parameters, self.VALUE, context)
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fields = layer.fields()
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idx = layer.fields().lookupField(fieldName)
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fieldType = fields[idx].type()
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if fieldType != QVariant.String and operator in self.STRING_OPERATORS:
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op = ''.join(['"%s", ' % o for o in self.STRING_OPERATORS])
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raise QgsProcessingException(
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self.tr('Operators {0} can be used only with string fields.').format(op))
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field_ref = QgsExpression.quotedColumnRef(fieldName)
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quoted_val = QgsExpression.quotedValue(value)
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if operator == 'is null':
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expression_string = '{} IS NULL'.format(field_ref)
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elif operator == 'is not null':
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expression_string = '{} IS NOT NULL'.format(field_ref)
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elif operator == 'begins with':
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expression_string = """%s LIKE '%s%%'""" % (field_ref, value)
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elif operator == 'contains':
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expression_string = """%s LIKE '%%%s%%'""" % (field_ref, value)
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elif operator == 'does not contain':
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expression_string = """%s NOT LIKE '%%%s%%'""" % (field_ref, value)
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else:
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expression_string = '{} {} {}'.format(field_ref, operator, quoted_val)
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expression = QgsExpression(expression_string)
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if expression.hasParserError():
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raise QgsProcessingException(expression.parserErrorString())
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layer.selectByExpression(expression_string)
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return {self.OUTPUT: parameters[self.INPUT]}
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