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refactor Select by attribute alg

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alexbruy committed Oct 3, 2014
1 parent 5d114a8 commit 3b60bd67a23d0b4cf953877adc3721f74d100045
@@ -77,6 +77,7 @@
from mmqgisx.DeleteDuplicateGeometries import DeleteDuplicateGeometries
from mmqgisx.TextToFloat import TextToFloat
from mmqgisx.ExtractByAttribute import ExtractByAttribute
from mmqgisx.SelectByAttribute import SelectByAttribute

from ConcaveHull import ConcaveHull
from Polygonize import Polygonize
@@ -143,6 +144,7 @@ def __init__(self):
# ------ mmqgisx ------
DeleteColumn(), DeleteDuplicateGeometries(),
TextToFloat(), ExtractByAttribute(),
SelectByAttribute(),
#mmqgisx_delete_duplicate_geometries_algorithm(),
#mmqgisx_geometry_convert_algorithm(),
#mmqgisx_grid_algorithm(),
@@ -0,0 +1,124 @@
# -*- coding: utf-8 -*-

"""
***************************************************************************
DeleteColumn.py
---------------------
Date : May 2010
Copyright : (C) 2010 by Michael Minn
Email : pyqgis at michaelminn dot com
***************************************************************************
* *
* 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 Minn'
__date__ = 'May 2010'
__copyright__ = '(C) 2010, Michael Minn'

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

__revision__ = '$Format:%H$'

from PyQt4.QtCore import *
from qgis.core import *
from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.core.GeoAlgorithmExecutionException import \
GeoAlgorithmExecutionException
from processing.core.parameters import ParameterVector
from processing.core.parameters import ParameterTableField
from processing.core.parameters import ParameterSelection
from processing.core.parameters import ParameterString
from processing.core.outputs import OutputVector
from processing.tools import dataobjects, vector


class SelectByAttribute(GeoAlgorithm):
INPUT = 'INPUT'
FIELD = 'FIELD'
OPERATOR = 'OPERATOR'
VALUE = 'VALUE'
OUTPUT = 'OUTPUT'

OPERATORS = ['=',
'!=',
'>',
'>=',
'<',
'<=',
'begins with',
'contains'
]

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

self.addParameter(ParameterVector(
self.INPUT, 'Input Layer', [ParameterVector.VECTOR_TYPE_ANY]))
self.addParameter(ParameterTableField(
self.FIELD, 'Selection attribute', self.INPUT))
self.addParameter(ParameterSelection(
self.OPERATOR, 'Operator', self.OPERATORS))
self.addParameter(ParameterString(self.VALUE, 'Value'))

self.addOutput(OutputVector(self.OUTPUT, 'Output'))

def processAlgorithm(self, progress):
layer = dataobjects.getObjectFromUri(
self.getParameterValue(self.INPUT))
fieldName = self.getParameterValue(self.FIELD)
operator = self.OPERATORS[self.getParameterValue(self.OPERATOR)]
value = self.getParameterValue(self.VALUE)

fields = layer.pendingFields()

idx = layer.fieldNameIndex(fieldName)
fieldType = fields[idx].type()

if fieldType != QVariant.String and operator in self.OPERATORS[-2:]:
op = ''.join(['"%s", ' % o for o in self.OPERATORS[-2:]])
raise GeoAlgorithmExecutionException(
'Operators %s can be used only with string fields.' % op)

if fieldType in [QVariant.Int, QVariant.Double]:
progress.setInfo('Numeric field')
expr = '"%s" %s %s' % (fieldName, operator, value)
progress.setInfo(expr)
elif fieldType == QVariant.String:
progress.setInfo('String field')
if operator not in self.OPERATORS[-2:]:
expr = """"%s" %s '%s'""" % (fieldName, operator, value)
elif operator == 'begins with':
expr = """"%s" LIKE '%s%%'""" % (fieldName, value)
elif operator == 'contains':
expr = """"%s" LIKE '%%%s%%'""" % (fieldName, value)
progress.setInfo(expr)
elif fieldType in [QVariant.Date, QVariant.DateTime]:
progress.setInfo('Date field')
expr = """"%s" %s '%s'""" % (fieldX, operator, value)
progress.setInfo(expr)
else:
raise GeoAlgorithmExecutionException(
'Unsupported field type "%s"' % fields[idx].typeName())

expression = QgsExpression(expr)
expression.prepare(fields)

features = vector.features(layer)

selected = []
count = len(features)
total = 100.0 / float(count)
for count, f in enumerate(features):
if expression.evaluate(f, fields):
selected.append(f.id())
progress.setPercentage(int(count * total))

layer.setSelectedFeatures(selected)
self.setOutputValue(self.OUTPUT, self.getParameterValue(self.INPUT))

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