本文整理汇总了Python中PyQt4.QtCore.QDate.isNull方法的典型用法代码示例。如果您正苦于以下问题：Python QDate.isNull方法的具体用法？Python QDate.isNull怎么用？Python QDate.isNull使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类PyQt4.QtCore.QDate的用法示例。
在下文中一共展示了QDate.isNull方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的Python代码示例。
示例1: processAlgorithm
# 需要导入模块: from PyQt4.QtCore import QDate [as 别名]
# 或者: from PyQt4.QtCore.QDate import isNull [as 别名]
def processAlgorithm(self, progress):
inLayer = dataobjects.getObjectFromUri(self.getParameterValue(self.INPUT))
boundary = self.getParameterValue(self.MODE) == self.MODE_BOUNDARY
smallestArea = self.getParameterValue(self.MODE) == self.MODE_SMALLEST_AREA
keepSelection = self.getParameterValue(self.KEEPSELECTION)
if not keepSelection:
# Make a selection with the values provided
attribute = self.getParameterValue(self.ATTRIBUTE)
comparison = self.comparisons[self.getParameterValue(self.COMPARISON)]
comparisonvalue = self.getParameterValue(self.COMPARISONVALUE)
selectindex = inLayer.dataProvider().fieldNameIndex(attribute)
selectType = inLayer.dataProvider().fields()[selectindex].type()
selectionError = False
if selectType == 2:
try:
y = int(comparisonvalue)
except ValueError:
selectionError = True
msg = self.tr('Cannot convert "%s" to integer' % unicode(comparisonvalue))
elif selectType == 6:
try:
y = float(comparisonvalue)
except ValueError:
selectionError = True
msg = self.tr('Cannot convert "%s" to float' % unicode(comparisonvalue))
elif selectType == 10:
# 10: string, boolean
try:
y = unicode(comparisonvalue)
except ValueError:
selectionError = True
msg = self.tr('Cannot convert "%s" to unicode' % unicode(comparisonvalue))
elif selectType == 14:
# date
dateAndFormat = comparisonvalue.split(' ')
if len(dateAndFormat) == 1:
# QtCore.QDate object
y = QLocale.system().toDate(dateAndFormat[0])
if y.isNull():
msg = self.tr('Cannot convert "%s" to date with system date format %s' % (unicode(dateAndFormat), QLocale.system().dateFormat()))
elif len(dateAndFormat) == 2:
y = QDate.fromString(dateAndFormat[0], dateAndFormat[1])
if y.isNull():
msg = self.tr('Cannot convert "%s" to date with format string "%s"' % (unicode(dateAndFormat[0]), dateAndFormat[1]))
else:
y = QDate()
msg = ''
if y.isNull():
# Conversion was unsuccessfull
selectionError = True
msg += self.tr('Enter the date and the date format, e.g. "07.26.2011" "MM.dd.yyyy".')
if (comparison == 'begins with' or comparison == 'contains') \
and selectType != 10:
selectionError = True
msg = self.tr('"%s" can only be used with string fields' % comparison)
selected = []
if selectionError:
raise GeoAlgorithmExecutionException(
self.tr('Error in selection input: %s' % msg))
else:
for feature in inLayer.getFeatures():
aValue = feature.attributes()[selectindex]
if aValue is None:
continue
if selectType == 2:
x = int(aValue)
elif selectType == 6:
x = float(aValue)
elif selectType == 10:
# 10: string, boolean
x = unicode(aValue)
elif selectType == 14:
# date
x = aValue # should be date
match = False
if comparison == '==':
match = x == y
elif comparison == '!=':
match = x != y
elif comparison == '>':
match = x > y
elif comparison == '>=':
match = x >= y
elif comparison == '<':
match = x < y
elif comparison == '<=':
#.........这里部分代码省略.........