QGIS/python/plugins/processing/algs/qgis/SelectByAttribute.py
2015-01-17 11:24:54 +02:00

125 lines
4.8 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
SelectByAttribute.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,
self.tr('Input Layer'), [ParameterVector.VECTOR_TYPE_ANY]))
self.addParameter(ParameterTableField(self.FIELD,
self.tr('Selection attribute'), self.INPUT))
self.addParameter(ParameterSelection(self.OPERATOR,
self.tr('Operator'), self.OPERATORS))
self.addParameter(ParameterString(self.VALUE, self.tr('Value')))
self.addOutput(OutputVector(self.OUTPUT, self.tr('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(
self.tr('Operators %s can be used only with string fields.' % op))
if fieldType in [QVariant.Int, QVariant.Double]:
progress.setInfo(self.tr('Numeric field'))
expr = '"%s" %s %s' % (fieldName, operator, value)
progress.setInfo(expr)
elif fieldType == QVariant.String:
progress.setInfo(self.tr('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(self.tr('Date field'))
expr = """"%s" %s '%s'""" % (fieldX, operator, value)
progress.setInfo(expr)
else:
raise GeoAlgorithmExecutionException(
self.tr('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))