def translate(self, expr, scope, **kwargs):
"""
Translate Ibis expression into a PySpark object.
All translated expressions are cached within scope. If an expression is
found within scope, it's returned. Otherwise, the it's translated and
cached for future reference.
:param expr: ibis expression
:param scope: dictionary mapping from operation to translated result
:param kwargs: parameters passed as keyword args (e.g. window)
:return: translated PySpark DataFrame or Column object
"""
# The operation node type the typed expression wraps
op = expr.op()
if op in scope:
return scope[op]
elif type(op) in self._registry:
formatter = self._registry[type(op)]
result = formatter(self, expr, scope, **kwargs)
scope[op] = result
return result
else:
raise com.OperationNotDefinedError(
'No translation rule for {}'.format(type(op)))
def execute_arbitrary_series_groupby(op, data, _, aggcontext=None, **kwargs):
how = op.how
if how is None:
how = 'first'
if how not in {'first', 'last'}:
raise com.OperationNotDefinedError(
'Arbitrary {!r} is not supported'.format(how))
return aggcontext.agg(data, how)
def execute_arbitrary_series_mask(op, data, mask, aggcontext=None, **kwargs):
if op.how == 'first':
index = 0
elif op.how == 'last':
index = -1
else:
raise com.OperationNotDefinedError(
'Arbitrary {!r} is not supported'.format(op.how))
data = data[mask] if mask is not None else data
return data.iloc[index]
def translate(self, expr, scope, **kwargs):
# The operation node type the typed expression wraps
op = expr.op()
if type(op) in self._registry:
formatter = self._registry[type(op)]
return formatter(self, expr, scope, **kwargs)
else:
raise com.OperationNotDefinedError(
'No translation rule for {}'.format(type(op))
)
def execute_arbitrary_series_mask(op, data, mask, aggcontext=None, **kwargs):
"""
Note: we cannot use the pandas version because Dask does not support .iloc
"""
if op.how == 'first':
index = 0
elif op.how == 'last':
index = -1
else:
raise com.OperationNotDefinedError(
'Arbitrary {!r} is not supported'.format(op.how))
data = data[mask] if mask is not None else data
return data.loc[index]
def execute_arbitrary_series_mask(op, data, mask, aggcontext=None, **kwargs):
"""
Note: we cannot use the pandas version because Dask does not support .iloc
See https://docs.dask.org/en/latest/dataframe-indexing.html. .loc will
only work if our index lines up with the label.
"""
data = data[mask] if mask is not None else data
if op.how == 'first':
index = 0
elif op.how == 'last':
index = len(data) - 1 # TODO - computation
else:
raise com.OperationNotDefinedError(
f'Arbitrary {op.how!r} is not supported')
return data.loc[index]
def translate(self, expr):
# The operation node type the typed expression wraps
op = expr.op()
if type(op) in self._rewrites: # even if type(op) is in self._registry
expr = self._rewrites[type(op)](expr)
op = expr.op()
# TODO: use op MRO for subclasses instead of this isinstance spaghetti
if isinstance(op, ops.ScalarParameter):
return self._trans_param(expr)
elif isinstance(op, ops.TableNode):
# HACK/TODO: revisit for more complex cases
return '*'
elif type(op) in self._registry:
formatter = self._registry[type(op)]
return formatter(self, expr)
else:
raise com.OperationNotDefinedError(
f'No translation rule for {type(op)}')
def execute_window_op(op,
data,
window,
scope=None,
aggcontext=None,
clients=None,
**kwargs):
operand = op.expr
# pre execute "manually" here because otherwise we wouldn't pickup
# relevant scope changes from the child operand since we're managing
# execution of that by hand
operand_op = operand.op()
pre_executed_scope = pre_execute(operand_op,
*clients,
scope=scope,
aggcontext=aggcontext,
**kwargs)
scope = toolz.merge(scope, pre_executed_scope)
(root, ) = op.root_tables()
root_expr = root.to_expr()
data = execute(
root_expr,
scope=scope,
clients=clients,
aggcontext=aggcontext,
**kwargs,
)
following = window.following
order_by = window._order_by
if (order_by and following != 0
and not isinstance(operand_op, ops.ShiftBase)):
raise com.OperationNotDefinedError(
'Window functions affected by following with order_by are not '
'implemented')
group_by = window._group_by
grouping_keys = [
key_op.name if isinstance(key_op, ops.TableColumn) else execute(
key, scope=scope, clients=clients, aggcontext=aggcontext, **kwargs)
for key, key_op in zip(group_by,
map(operator.methodcaller('op'), group_by))
]
order_by = window._order_by
if not order_by:
ordering_keys = ()
if group_by:
if order_by:
(
sorted_df,
grouping_keys,
ordering_keys,
) = util.compute_sorted_frame(data,
order_by,
group_by=group_by,
**kwargs)
source = sorted_df.groupby(grouping_keys, sort=True)
post_process = _post_process_group_by_order_by
else:
source = data.groupby(grouping_keys, sort=False)
post_process = _post_process_group_by
else:
if order_by:
source, grouping_keys, ordering_keys = util.compute_sorted_frame(
data, order_by, **kwargs)
post_process = _post_process_order_by
else:
source = data
post_process = _post_process_empty
new_scope = toolz.merge(
scope,
OrderedDict((t, source) for t in operand.op().root_tables()),
factory=OrderedDict,
)
# figure out what the dtype of the operand is
operand_type = operand.type()
operand_dtype = operand_type.to_pandas()
aggcontext = get_aggcontext(
window,
operand=operand,
operand_dtype=operand_dtype,
parent=source,
group_by=grouping_keys,
order_by=ordering_keys,
)
result = execute(
operand,
scope=new_scope,
aggcontext=aggcontext,
clients=clients,
**kwargs,
)
series = post_process(result, data, ordering_keys, grouping_keys)
assert len(data) == len(
series
), 'input data source and computed column do not have the same length'
return series
def operation(op, expr):
raise com.OperationNotDefinedError(f'No translation rule for {type(op)}')
def execute_window_op(
op,
data,
window,
scope: Scope = None,
timecontext: Optional[TimeContext] = None,
aggcontext=None,
clients=None,
**kwargs,
):
operand = op.expr
# pre execute "manually" here because otherwise we wouldn't pickup
# relevant scope changes from the child operand since we're managing
# execution of that by hand
operand_op = operand.op()
adjusted_timecontext = None
if timecontext:
arg_timecontexts = compute_time_context(
op, timecontext=timecontext, clients=clients
)
# timecontext is the original time context required by parent node
# of this WindowOp, while adjusted_timecontext is the adjusted context
# of this Window, since we are doing a manual execution here, use
# adjusted_timecontext in later execution phases
adjusted_timecontext = arg_timecontexts[0]
pre_executed_scope = pre_execute(
operand_op,
*clients,
scope=scope,
timecontext=adjusted_timecontext,
aggcontext=aggcontext,
**kwargs,
)
scope = scope.merge_scope(pre_executed_scope)
(root,) = op.root_tables()
root_expr = root.to_expr()
data = execute(
root_expr,
scope=scope,
timecontext=adjusted_timecontext,
clients=clients,
aggcontext=aggcontext,
**kwargs,
)
following = window.following
order_by = window._order_by
if (
order_by
and following != 0
and not isinstance(operand_op, ops.ShiftBase)
):
raise com.OperationNotDefinedError(
'Window functions affected by following with order_by are not '
'implemented'
)
group_by = window._group_by
grouping_keys = [
key_op.name
if isinstance(key_op, ops.TableColumn)
else execute(
key,
scope=scope,
clients=clients,
timecontext=adjusted_timecontext,
aggcontext=aggcontext,
**kwargs,
)
for key, key_op in zip(
group_by, map(operator.methodcaller('op'), group_by)
)
]
order_by = window._order_by
if not order_by:
ordering_keys = []
if group_by:
if order_by:
(
sorted_df,
grouping_keys,
ordering_keys,
) = util.compute_sorted_frame(
data,
order_by,
group_by=group_by,
timecontext=adjusted_timecontext,
**kwargs,
)
source = sorted_df.groupby(grouping_keys, sort=True)
post_process = _post_process_group_by_order_by
else:
source = data.groupby(grouping_keys, sort=False)
post_process = _post_process_group_by
else:
if order_by:
source, grouping_keys, ordering_keys = util.compute_sorted_frame(
data, order_by, timecontext=adjusted_timecontext, **kwargs
)
post_process = _post_process_order_by
else:
source = data
post_process = _post_process_empty
# Here groupby object should be add to the corresponding node in scope
# for execution, data will be overwrite to a groupby object, so we
# force an update regardless of time context
new_scope = scope.merge_scopes(
[
Scope({t: source}, adjusted_timecontext)
for t in operand.op().root_tables()
],
overwrite=True,
)
aggcontext = get_aggcontext(
window,
scope=scope,
operand=operand,
parent=source,
group_by=grouping_keys,
order_by=ordering_keys,
**kwargs,
)
result = execute(
operand,
scope=new_scope,
timecontext=adjusted_timecontext,
aggcontext=aggcontext,
clients=clients,
**kwargs,
)
series = post_process(
result, data, ordering_keys, grouping_keys, adjusted_timecontext,
)
assert len(data) == len(
series
), 'input data source and computed column do not have the same length'
# trim data to original time context
series = trim_with_timecontext(series, timecontext)
return series
def execute_window_op(op,
data,
window,
scope=None,
aggcontext=None,
clients=None,
**kwargs):
operand = op.expr
# pre execute "manually" here because otherwise we wouldn't pickup
# relevant scope changes from the child operand since we're managing
# execution of that by hand
operand_op = operand.op()
pre_executed_scope = pre_execute(operand_op,
*clients,
scope=scope,
aggcontext=aggcontext,
**kwargs)
scope = toolz.merge(scope, pre_executed_scope)
(root, ) = op.root_tables()
root_expr = root.to_expr()
data = execute(
root_expr,
scope=scope,
clients=clients,
aggcontext=aggcontext,
**kwargs,
)
following = window.following
order_by = window._order_by
if (order_by and following != 0
and not isinstance(operand_op, ops.ShiftBase)):
raise com.OperationNotDefinedError(
'Window functions affected by following with order_by are not '
'implemented')
group_by = window._group_by
grouping_keys = [
key_op.name if isinstance(key_op, ops.TableColumn) else execute(
key, scope=scope, clients=clients, aggcontext=aggcontext, **kwargs)
for key, key_op in zip(group_by,
map(operator.methodcaller('op'), group_by))
]
order_by = window._order_by
if not order_by:
ordering_keys = ()
if group_by:
if order_by:
(
sorted_df,
grouping_keys,
ordering_keys,
) = util.compute_sorted_frame(data,
order_by,
group_by=group_by,
**kwargs)
source = sorted_df.groupby(grouping_keys, sort=True)
post_process = _post_process_group_by_order_by
else:
source = data.groupby(grouping_keys, sort=False)
post_process = _post_process_group_by
else:
if order_by:
source, grouping_keys, ordering_keys = util.compute_sorted_frame(
data, order_by, **kwargs)
post_process = _post_process_order_by
else:
source = data
post_process = _post_process_empty
new_scope = toolz.merge(
scope,
OrderedDict((t, source) for t in operand.op().root_tables()),
factory=OrderedDict,
)
# figure out what the dtype of the operand is
operand_type = operand.type()
operand_dtype = operand_type.to_pandas()
# no order by or group by: default summarization aggcontext
#
# if we're reducing and we have an order by expression then we need to
# expand or roll.
#
# otherwise we're transforming
if not grouping_keys and not ordering_keys:
aggcontext = agg_ctx.Summarize()
elif (isinstance(operand.op(),
(ops.Reduction, ops.CumulativeOp, ops.Any, ops.All))
and ordering_keys):
# XXX(phillipc): What a horror show
preceding = window.preceding
if preceding is not None:
max_lookback = window.max_lookback
assert not isinstance(operand.op(), ops.CumulativeOp)
aggcontext = agg_ctx.Moving(
preceding,
max_lookback,
parent=source,
group_by=grouping_keys,
order_by=ordering_keys,
dtype=operand_dtype,
)
else:
# expanding window
aggcontext = agg_ctx.Cumulative(
parent=source,
group_by=grouping_keys,
order_by=ordering_keys,
dtype=operand_dtype,
)
else:
# groupby transform (window with a partition by clause in SQL parlance)
aggcontext = agg_ctx.Transform(
parent=source,
group_by=grouping_keys,
order_by=ordering_keys,
dtype=operand_dtype,
)
result = execute(
operand,
scope=new_scope,
aggcontext=aggcontext,
clients=clients,
**kwargs,
)
series = post_process(result, data, ordering_keys, grouping_keys)
assert len(data) == len(
series
), 'input data source and computed column do not have the same length'
return series