QGIS/python/plugins/processing/algs/qgis/StatisticsByCategories.py
Nyall Dawson 427c3b1684 Remove vector.features
Use QgsProcessingUtils.getFeatures instead
2017-04-26 12:53:35 +10:00

107 lines
4.5 KiB
Python

# -*- coding: utf-8 -*-
"""
***************************************************************************
StatisticsByCategories.py
---------------------
Date : September 2012
Copyright : (C) 2012 by Victor Olaya
Email : volayaf at gmail 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. *
* *
***************************************************************************
"""
from builtins import str
__author__ = 'Victor Olaya'
__date__ = 'September 2012'
__copyright__ = '(C) 2012, Victor Olaya'
# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'
from qgis.core import (QgsApplication,
QgsStatisticalSummary,
QgsProcessingUtils)
from processing.core.outputs import OutputTable
from processing.core.GeoAlgorithm import GeoAlgorithm
from processing.tools import dataobjects, vector
from processing.core.parameters import ParameterVector
from processing.core.parameters import ParameterTableField
class StatisticsByCategories(GeoAlgorithm):
INPUT_LAYER = 'INPUT_LAYER'
VALUES_FIELD_NAME = 'VALUES_FIELD_NAME'
CATEGORIES_FIELD_NAME = 'CATEGORIES_FIELD_NAME'
OUTPUT = 'OUTPUT'
def icon(self):
return QgsApplication.getThemeIcon("/providerQgis.svg")
def svgIconPath(self):
return QgsApplication.iconPath("providerQgis.svg")
def group(self):
return self.tr('Vector table tools')
def name(self):
return 'statisticsbycategories'
def displayName(self):
return self.tr('Statistics by categories')
def defineCharacteristics(self):
self.addParameter(ParameterVector(self.INPUT_LAYER,
self.tr('Input vector layer')))
self.addParameter(ParameterTableField(self.VALUES_FIELD_NAME,
self.tr('Field to calculate statistics on'),
self.INPUT_LAYER, ParameterTableField.DATA_TYPE_NUMBER))
self.addParameter(ParameterTableField(self.CATEGORIES_FIELD_NAME,
self.tr('Field with categories'),
self.INPUT_LAYER, ParameterTableField.DATA_TYPE_ANY))
self.addOutput(OutputTable(self.OUTPUT, self.tr('Statistics by category')))
def processAlgorithm(self, context, feedback):
layer = dataobjects.getLayerFromString(self.getParameterValue(self.INPUT_LAYER))
valuesFieldName = self.getParameterValue(self.VALUES_FIELD_NAME)
categoriesFieldName = self.getParameterValue(self.CATEGORIES_FIELD_NAME)
output = self.getOutputFromName(self.OUTPUT)
valuesField = layer.fields().lookupField(valuesFieldName)
categoriesField = layer.fields().lookupField(categoriesFieldName)
features = QgsProcessingUtils.getFeatures(layer, context)
total = 100.0 / QgsProcessingUtils.featureCount(layer, context)
values = {}
for current, feat in enumerate(features):
feedback.setProgress(int(current * total))
attrs = feat.attributes()
try:
value = float(attrs[valuesField])
cat = str(attrs[categoriesField])
if cat not in values:
values[cat] = []
values[cat].append(value)
except:
pass
fields = ['category', 'min', 'max', 'mean', 'stddev', 'sum', 'count']
writer = output.getTableWriter(fields)
stat = QgsStatisticalSummary(QgsStatisticalSummary.Min | QgsStatisticalSummary.Max |
QgsStatisticalSummary.Mean | QgsStatisticalSummary.StDevSample |
QgsStatisticalSummary.Sum | QgsStatisticalSummary.Count)
for (cat, v) in list(values.items()):
stat.calculate(v)
record = [cat, stat.min(), stat.max(), stat.mean(), stat.sampleStDev(), stat.sum(), stat.count()]
writer.addRecord(record)