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[processing] added 'Select by expression' algorithm (by Michaël Douch…
…in - 3Liz)
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volaya committed Jul 6, 2014
1 parent 6026944 commit 1088ba7998119545b76cfb84b675aabc546df723
Showing with 82 additions and 1 deletion.
  1. +2 −1 python/plugins/processing/algs/qgis/QGISAlgorithmProvider.py
  2. +80 −0 python/plugins/processing/algs/qgis/SelectByExpression.py
@@ -101,6 +101,7 @@
from ImportIntoPostGIS import ImportIntoPostGIS
from SetVectorStyle import SetVectorStyle
from SetRasterStyle import SetRasterStyle
from SelectByExpression import SelectByExpression
# from VectorLayerHistogram import VectorLayerHistogram
# from VectorLayerScatterplot import VectorLayerScatterplot
# from MeanAndStdDevPlot import MeanAndStdDevPlot
@@ -157,7 +158,7 @@ def __init__(self):
RandomPointsPolygonsVariable(),
RandomPointsAlongLines(), PointsToPaths(),
PostGISExecuteSQL(), ImportIntoPostGIS(),
SetVectorStyle(), SetRasterStyle(),
SetVectorStyle(), SetRasterStyle(), SelectByExpression()
# ------ raster ------
# CreateConstantRaster(),
# ------ graphics ------
@@ -0,0 +1,80 @@
# -*- coding: utf-8 -*-

"""
***************************************************************************
SelectByExpression.py
---------------------
Date : July 2014
Copyright : (C) 2014 by Michaël Douchin
***************************************************************************
* *
* 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 Douchin'
__date__ = 'July 2014'
__copyright__ = '(C) 2014, Michael Douchin'

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

__revision__ = '$Format:%H$'

import processing
from qgis.core import *
from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
from processing.parameters.ParameterVector import ParameterVector
from processing.parameters.ParameterSelection import ParameterSelection
from processing.outputs.OutputVector import OutputVector
from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.parameters.ParameterString import ParameterString

class SelectByExpression(GeoAlgorithm):

LAYERNAME = 'LAYERNAME'
EXPRESSION= 'EXPRESSION'
RESULT = 'RESULT'
METHOD = 'METHOD'
METHODS = ['creating new selection', 'adding to current selection',
'removing from current selection']

def defineCharacteristics(self):
self.name = 'Select by expression'
self.group = 'Vector selection tools'

self.addParameter(ParameterVector(self.LAYERNAME, 'Input Layer',
[ParameterVector.VECTOR_TYPE_ANY]))
self.addParameter(ParameterString(self.EXPRESSION, "Expression"))
self.addParameter(ParameterSelection(self.METHOD,
'Modify current selection by', self.METHODS, 0))
self.addOutput(OutputVector(self.RESULT, 'Output', True))

def processAlgorithm(self, progress):

filename = self.getParameterValue(self.LAYERNAME)
layer = processing.getObject(filename)
oldSelection = set(layer.selectedFeaturesIds())
method = self.getParameterValue(self.METHOD)

# Build QGIS request with expression
expression = self.getParameterValue(self.EXPRESSION)
qExp = QgsExpression(expression)
if not qExp.hasParserError():
qReq = QgsFeatureRequest(qExp)
else:
raise GeoAlgorithmExecutionException(qExp.parserErrorString())
selected = [f.id() for f in layer.getFeatures(qReq)]

if method == 1:
selected = list(oldSelection.union(selected))
elif method == 2:
selected = list(oldSelection.difference(selected))

# Set the selection
layer.setSelectedFeatures(selected)

self.setOutputValue(self.RESULT, filename)

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