2017-07-07 09:27:35 +10:00

114 lines
4.3 KiB
Python

# -*- 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 qgis.core import (QgsApplication,
QgsFeatureSink,
QgsProcessingUtils,
QgsProcessingParameterFeatureSource,
QgsProcessingParameterFeatureSink,
QgsProcessingParameterField,
QgsProcessingOutputVectorLayer)
from processing.algs.qgis.QgisAlgorithm import QgisAlgorithm
class DeleteColumn(QgisAlgorithm):
INPUT = 'INPUT'
COLUMNS = 'COLUMN'
OUTPUT = 'OUTPUT'
def tags(self):
return self.tr('drop,delete,remove,fields,columns,attributes').split(',')
def group(self):
return self.tr('Vector table tools')
def __init__(self):
super().__init__()
self.addParameter(QgsProcessingParameterFeatureSource(self.INPUT, self.tr('Input layer')))
self.addParameter(QgsProcessingParameterField(self.COLUMNS,
self.tr('Fields to drop'),
None, self.INPUT, QgsProcessingParameterField.Any, True))
self.addParameter(QgsProcessingParameterFeatureSink(self.OUTPUT, self.tr('Output layer')))
self.addOutput(QgsProcessingOutputVectorLayer(self.OUTPUT, self.tr("Output layer")))
self.source = None
self.fields_to_delete = None
self.sink = None
self.dest_id = None
self.field_indices = []
def name(self):
return 'deletecolumn'
def displayName(self):
return self.tr('Drop field(s)')
def prepareAlgorithm(self, parameters, context, feedback):
self.source = self.parameterAsSource(parameters, self.INPUT, context)
self.fields_to_delete = self.parameterAsFields(parameters, self.COLUMNS, context)
fields = self.source.fields()
# loop through twice - first we need to build up a list of original attribute indices
for f in self.fields_to_delete:
index = fields.lookupField(f)
self.field_indices.append(index)
# important - make sure we remove from the end so we aren't changing used indices as we go
self.field_indices.sort(reverse=True)
# this second time we make a cleaned version of the fields
for index in self.field_indices:
fields.remove(index)
(self.sink, self.dest_id) = self.parameterAsSink(parameters, self.OUTPUT, context,
fields, self.source.wkbType(), self.source.sourceCrs())
return True
def processAlgorithm(self, context, feedback):
features = self.source.getFeatures()
total = 100.0 / self.source.featureCount() if self.source.featureCount() else 0
for current, f in enumerate(features):
if feedback.isCanceled():
break
attributes = f.attributes()
for index in self.field_indices:
del attributes[index]
f.setAttributes(attributes)
self.sink.addFeature(f, QgsFeatureSink.FastInsert)
feedback.setProgress(int(current * total))
return True
def postProcessAlgorithm(self, context, feedback):
return {self.OUTPUT: self.dest_id}