def write_feature_to_excel(self, sheet, idx, feat):
sheet.write(idx, self.excelFkIdx, feat[self.shpKeyName])
for (fieldName, exp) in self.s.expressions.iteritems():
fieldIdx = field_idx_from_name(self.excelName, fieldName)
exp = QgsExpression(exp)
sheet.write(idx, fieldIdx, exp.evaluate(feat))
def write_feature_to_excel(self, sheet, idx, feat):
sheet.write(idx, self.excelFkIdx, feat[self.shpKeyName])
for (fieldName, exp) in self.s.expressions.iteritems():
fieldIdx = field_idx_from_name(self.excelName, fieldName)
exp = QgsExpression(exp)
sheet.write(idx, fieldIdx, exp.evaluate(feat))
def register_function(function, arg_count, group, usesgeometry=False,
referenced_columns=[QgsFeatureRequest.ALL_ATTRIBUTES], **kwargs):
"""
Register a Python function to be used as a expression function.
Functions should take (values, feature, parent) as args:
Example:
def myfunc(values, feature, parent):
pass
They can also shortcut naming feature and parent args by using *args
if they are not needed in the function.
Example:
def myfunc(values, *args):
pass
Functions should return a value compatible with QVariant
Eval errors can be raised using parent.setEvalErrorString("Error message")
:param function:
:param arg_count:
:param group:
:param usesgeometry:
:return:
"""
class QgsPyExpressionFunction(QgsExpressionFunction):
def __init__(self, func, name, args, group, helptext='', usesGeometry=True,
referencedColumns=QgsFeatureRequest.ALL_ATTRIBUTES, expandargs=False):
QgsExpressionFunction.__init__(self, name, args, group, helptext)
self.function = func
self.expandargs = expandargs
self.uses_geometry = usesGeometry
self.referenced_columns = referencedColumns
def func(self, values, context, parent, node):
feature = None
if context:
feature = context.feature()
try:
if self.expandargs:
values.append(feature)
values.append(parent)
if inspect.getargspec(self.function).args[-1] == 'context':
values.append(context)
return self.function(*values)
else:
if inspect.getargspec(self.function).args[-1] == 'context':
self.function(values, feature, parent, context)
return self.function(values, feature, parent)
except Exception as ex:
parent.setEvalErrorString(str(ex))
return None
def usesGeometry(self, node):
return self.uses_geometry
def referencedColumns(self, node):
return self.referenced_columns
helptemplate = string.Template("""<h3>$name function</h3><br>$doc""")
name = kwargs.get('name', function.__name__)
helptext = kwargs.get('helpText') or function.__doc__ or ''
helptext = helptext.strip()
expandargs = False
if arg_count == "auto":
# Work out the number of args we need.
# Number of function args - 2. The last two args are always feature, parent.
args = inspect.getargspec(function).args
number = len(args)
arg_count = number - 2
if args[-1] == 'context':
arg_count -= 1
expandargs = True
register = kwargs.get('register', True)
if register and QgsExpression.isFunctionName(name):
if not QgsExpression.unregisterFunction(name):
msgtitle = QCoreApplication.translate("UserExpressions", "User expressions")
msg = QCoreApplication.translate("UserExpressions",
"The user expression {0} already exists and could not be unregistered.").format(
name)
QgsMessageLog.logMessage(msg + "\n", msgtitle, Qgis.Warning)
return None
function.__name__ = name
helptext = helptemplate.safe_substitute(name=name, doc=helptext)
f = QgsPyExpressionFunction(function, name, arg_count, group, helptext, usesgeometry, referenced_columns,
expandargs)
# This doesn't really make any sense here but does when used from a decorator context
# so it can stay.
if register:
QgsExpression.registerFunction(f)
return f
def register_function(function, arg_count, group, usesgeometry=False,
referenced_columns=[QgsFeatureRequest.ALL_ATTRIBUTES], handlesnull=False, **kwargs):
"""
Register a Python function to be used as a expression function.
Functions should take (values, feature, parent) as args:
Example:
def myfunc(values, feature, parent):
pass
They can also shortcut naming feature and parent args by using *args
if they are not needed in the function.
Example:
def myfunc(values, *args):
pass
Functions should return a value compatible with QVariant
Eval errors can be raised using parent.setEvalErrorString("Error message")
:param function:
:param arg_count:
:param group:
:param usesgeometry:
:param handlesnull: Needs to be set to True if this function does not always return NULL if any parameter is NULL. Default False.
:return:
"""
class QgsPyExpressionFunction(QgsExpressionFunction):
def __init__(self, func, name, args, group, helptext='', usesGeometry=True,
referencedColumns=QgsFeatureRequest.ALL_ATTRIBUTES, expandargs=False, handlesNull=False):
QgsExpressionFunction.__init__(self, name, args, group, helptext)
self.function = func
self.expandargs = expandargs
self.uses_geometry = usesGeometry
self.referenced_columns = referencedColumns
self.handles_null = handlesNull
def func(self, values, context, parent, node):
feature = None
if context:
feature = context.feature()
try:
if self.expandargs:
values.append(feature)
values.append(parent)
if inspect.getfullargspec(self.function).args[-1] == 'context':
values.append(context)
return self.function(*values)
else:
if inspect.getfullargspec(self.function).args[-1] == 'context':
self.function(values, feature, parent, context)
return self.function(values, feature, parent)
except Exception as ex:
parent.setEvalErrorString(str(ex))
return None
def usesGeometry(self, node):
return self.uses_geometry
def referencedColumns(self, node):
return self.referenced_columns
def handlesNull(self):
return self.handles_null
helptemplate = string.Template("""<h3>$name function</h3><br>$doc""")
name = kwargs.get('name', function.__name__)
helptext = kwargs.get('helpText') or function.__doc__ or ''
helptext = helptext.strip()
expandargs = False
if arg_count == "auto":
# Work out the number of args we need.
# Number of function args - 2. The last two args are always feature, parent.
args = inspect.getfullargspec(function).args
number = len(args)
arg_count = number - 2
if args[-1] == 'context':
arg_count -= 1
expandargs = True
register = kwargs.get('register', True)
if register and QgsExpression.isFunctionName(name):
if not QgsExpression.unregisterFunction(name):
msgtitle = QCoreApplication.translate("UserExpressions", "User expressions")
msg = QCoreApplication.translate("UserExpressions",
"The user expression {0} already exists and could not be unregistered.").format(
name)
QgsMessageLog.logMessage(msg + "\n", msgtitle, Qgis.Warning)
return None
function.__name__ = name
helptext = helptemplate.safe_substitute(name=name, doc=helptext)
f = QgsPyExpressionFunction(function, name, arg_count, group, helptext, usesgeometry, referenced_columns,
expandargs, handlesnull)
# This doesn't really make any sense here but does when used from a decorator context
# so it can stay.
if register:
QgsExpression.registerFunction(f)
return f
def add_data_defined_expression(self, field_name: str, expression: str):
self.data_defined_expressions[field_name] = QgsExpression(expression)