def populateByExpression(self, adding=False):
"""
Populates the panel using an expression
"""
context = dataobjects.createContext()
expression_context = context.expressionContext()
# use the first row parameter values as a preview during expression creation
params = self.panel.parametersForRow(0, warnOnInvalid=False)
alg_scope = QgsExpressionContextUtils.processingAlgorithmScope(self.panel.alg, params, context)
# create explicit variables corresponding to every parameter
for k, v in params.items():
alg_scope.setVariable(k, v, True)
expression_context.appendScope(alg_scope)
# mark the parameter variables as highlighted for discoverability
highlighted_vars = expression_context.highlightedVariables()
highlighted_vars.extend(list(params.keys()))
expression_context.setHighlightedVariables(highlighted_vars)
dlg = QgsExpressionBuilderDialog(layer=None, context=context.expressionContext())
if adding:
dlg.setExpectedOutputFormat(self.tr('An array of values corresponding to each new row to add'))
if not dlg.exec_():
return
if adding:
exp = QgsExpression(dlg.expressionText())
res = exp.evaluate(expression_context)
if type(res) is not list:
res = [res]
first_row = self.panel.batchRowCount() if self.panel.batchRowCount() > 1 else 0
for row, value in enumerate(res):
self.setRowValue(row + first_row, value, context)
else:
for row in range(self.panel.batchRowCount()):
params = self.panel.parametersForRow(row, warnOnInvalid=False)
# remove previous algorithm scope -- we need to rebuild this completely, using the
# other parameter values from the current row
expression_context.popScope()
alg_scope = QgsExpressionContextUtils.processingAlgorithmScope(self.panel.alg, params, context)
for k, v in params.items():
alg_scope.setVariable(k, v, True)
expression_context.appendScope(alg_scope)
# rebuild a new expression every time -- we don't want the expression compiler to replace
# variables with precompiled values
exp = QgsExpression(dlg.expressionText())
value = exp.evaluate(expression_context)
self.setRowValue(row, value, context)
def populateByExpression(self, adding=False):
"""
Populates the panel using an expression
"""
context = dataobjects.createContext()
expression_context = context.expressionContext()
# use the first row parameter values as a preview during expression creation
params, ok = self.panel.parametersForRow(0, warnOnInvalid=False)
alg_scope = QgsExpressionContextUtils.processingAlgorithmScope(
self.panel.alg, params, context)
# create explicit variables corresponding to every parameter
for k, v in params.items():
alg_scope.setVariable(k, v, True)
# add batchCount in the alg scope to be used in the expressions. 0 is only an example value
alg_scope.setVariable('row_number', 0, False)
expression_context.appendScope(alg_scope)
# mark the parameter variables as highlighted for discoverability
highlighted_vars = expression_context.highlightedVariables()
highlighted_vars.extend(list(params.keys()))
highlighted_vars.append('row_number')
expression_context.setHighlightedVariables(highlighted_vars)
dlg = QgsExpressionBuilderDialog(layer=None,
context=context.expressionContext())
if adding:
dlg.setExpectedOutputFormat(
self.tr(
'An array of values corresponding to each new row to add'))
if not dlg.exec_():
return
if adding:
exp = QgsExpression(dlg.expressionText())
res = exp.evaluate(expression_context)
if type(res) is not list:
res = [res]
first_row = self.panel.batchRowCount(
) if self.panel.batchRowCount() > 1 else 0
self.panel.addRow(len(res))
self.panel.tblParameters.setUpdatesEnabled(False)
for row, value in enumerate(res):
self.setRowValue(row + first_row, value, context)
self.panel.tblParameters.setUpdatesEnabled(True)
else:
self.panel.tblParameters.setUpdatesEnabled(False)
for row in range(self.panel.batchRowCount()):
params, ok = self.panel.parametersForRow(row,
warnOnInvalid=False)
# remove previous algorithm scope -- we need to rebuild this completely, using the
# other parameter values from the current row
expression_context.popScope()
alg_scope = QgsExpressionContextUtils.processingAlgorithmScope(
self.panel.alg, params, context)
for k, v in params.items():
alg_scope.setVariable(k, v, True)
# add batch row number as evaluable variable in algorithm scope
alg_scope.setVariable('row_number', row, False)
expression_context.appendScope(alg_scope)
# rebuild a new expression every time -- we don't want the expression compiler to replace
# variables with precompiled values
exp = QgsExpression(dlg.expressionText())
value = exp.evaluate(expression_context)
self.setRowValue(row, value, context)
self.panel.tblParameters.setUpdatesEnabled(True)
