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134 lines
5.4 KiB
Python
Executable File
134 lines
5.4 KiB
Python
Executable File
# -*- coding: utf-8 -*-
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"""
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***************************************************************************
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ExtractByAttribute.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, QgsFeatureRequest
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from processing.core.GeoAlgorithm import GeoAlgorithm
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from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
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from processing.core.parameters import ParameterVector
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from processing.core.parameters import ParameterTableField
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from processing.core.parameters import ParameterSelection
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from processing.core.parameters import ParameterString
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from processing.core.outputs import OutputVector
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from processing.tools import dataobjects
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class ExtractByAttribute(GeoAlgorithm):
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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 defineCharacteristics(self):
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self.name, self.i18n_name = self.trAlgorithm('Extract by attribute')
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self.group, self.i18n_group = self.trAlgorithm('Vector selection tools')
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self.tags = self.tr('extract,filter,attribute,value,contains,null,field')
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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(ParameterVector(self.INPUT,
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self.tr('Input Layer')))
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self.addParameter(ParameterTableField(self.FIELD,
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self.tr('Selection attribute'), self.INPUT))
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self.addParameter(ParameterSelection(self.OPERATOR,
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self.tr('Operator'), self.i18n_operators))
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self.addParameter(ParameterString(self.VALUE, self.tr('Value'), optional=True))
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self.addOutput(OutputVector(self.OUTPUT, self.tr('Extracted (attribute)')))
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def processAlgorithm(self, feedback):
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layer = dataobjects.getObjectFromUri(self.getParameterValue(self.INPUT))
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fieldName = self.getParameterValue(self.FIELD)
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operator = self.OPERATORS[self.getParameterValue(self.OPERATOR)]
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value = self.getParameterValue(self.VALUE)
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fields = layer.fields()
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writer = self.getOutputFromName(self.OUTPUT).getVectorWriter(fields,
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layer.wkbType(), layer.crs())
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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 GeoAlgorithmExecutionException(
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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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expr = '{} IS NULL'.format(field_ref)
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elif operator == 'is not null':
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expr = '{} IS NOT NULL'.format(field_ref)
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elif operator == 'begins with':
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expr = """%s LIKE '%s%%'""" % (field_ref, value)
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elif operator == 'contains':
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expr = """%s LIKE '%%%s%%'""" % (field_ref, value)
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elif operator == 'does not contain':
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expr = """%s NOT LIKE '%%%s%%'""" % (field_ref, value)
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else:
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expr = '{} {} {}'.format(field_ref, operator, quoted_val)
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expression = QgsExpression(expr)
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if not expression.hasParserError():
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req = QgsFeatureRequest(expression)
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else:
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raise GeoAlgorithmExecutionException(expression.parserErrorString())
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for f in layer.getFeatures(req):
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writer.addFeature(f)
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del writer
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