def infer_pandas_schema(df, schema=None):
schema = schema if schema is not None else {}
pairs = []
for column_name, pandas_dtype in df.dtypes.iteritems():
if not isinstance(column_name, str):
raise TypeError(
'Column names must be strings to use the pandas backend'
)
if column_name in schema:
ibis_dtype = dt.dtype(schema[column_name])
elif pandas_dtype == np.object_:
inferred_dtype = infer_pandas_dtype(df[column_name], skipna=True)
if inferred_dtype in {'mixed', 'decimal'}:
# TODO: in principal we can handle decimal (added in pandas
# 0.23)
raise TypeError(
'Unable to infer type of column {0!r}. Try instantiating '
'your table from the client with client.table('
"'my_table', schema={{{0!r}: <explicit type>}})".format(
column_name
)
)
ibis_dtype = _inferable_pandas_dtypes[inferred_dtype]
else:
ibis_dtype = dt.dtype(pandas_dtype)
pairs.append((column_name, ibis_dtype))
return sch.schema(pairs)
def schema_from_table(table, schema=None):
"""Retrieve an ibis schema from a SQLAlchemy ``Table``.
Parameters
----------
table : sa.Table
Returns
-------
schema : ibis.expr.datatypes.Schema
An ibis schema corresponding to the types of the columns in `table`.
"""
schema = schema if schema is not None else {}
pairs = []
for name, column in table.columns.items():
if name in schema:
dtype = dt.dtype(schema[name])
else:
dtype = dt.dtype(
getattr(table.bind, 'dialect', SQLAlchemyDialect()),
column.type,
nullable=column.nullable,
)
pairs.append((name, dtype))
return sch.schema(pairs)
def test_literal_promotions(table, op, name, case, ex_type):
col = table[name]
result = op(col, case)
assert result.type() == dt.dtype(ex_type)
result = op(case, col)
assert result.type() == dt.dtype(ex_type)
def test_interval_unvalid_unit(unit):
definition = "interval('{}')".format(unit)
with pytest.raises(ValueError):
dt.dtype(definition)
with pytest.raises(ValueError):
dt.Interval(dt.int32, unit)
def test_interval(unit):
definition = "interval('{}')".format(unit)
dt.Interval(unit, dt.int32) == dt.dtype(definition)
definition = "interval<uint16>('{}')".format(unit)
dt.Interval(unit, dt.uint16) == dt.dtype(definition)
definition = "interval<int64>('{}')".format(unit)
dt.Interval(unit, dt.int64) == dt.dtype(definition)
def test_string_to_number(table, type):
casted = table.g.cast(type)
casted_literal = ibis.literal('5').cast(type).name('bar')
assert isinstance(casted, ir.ColumnExpr)
assert casted.type() == dt.dtype(type)
assert isinstance(casted_literal, ir.ScalarExpr)
assert casted_literal.type() == dt.dtype(type)
assert casted_literal.get_name() == 'bar'
def param(type):
"""Create a parameter of a particular type to be defined just before
execution.
Parameters
----------
type : dt.DataType
The type of the unbound parameter, e.g., double, int64, date, etc.
Returns
-------
ScalarExpr
Examples
--------
>>> import ibis
>>> import ibis.expr.datatypes as dt
>>> start = ibis.param(dt.date)
>>> end = ibis.param(dt.date)
>>> schema = [('timestamp_col', 'timestamp'), ('value', 'double')]
>>> t = ibis.table(schema)
>>> predicates = [t.timestamp_col >= start, t.timestamp_col <= end]
>>> expr = t.filter(predicates).value.sum()
"""
import ibis.expr.datatypes as dt
import ibis.expr.operations as ops
return ops.ScalarParameter(dt.dtype(type)).to_expr()
def sa_array(dialect, satype, nullable=True):
dimensions = satype.dimensions
if dimensions is not None and dimensions != 1:
raise NotImplementedError('Nested array types not yet supported')
value_dtype = dt.dtype(dialect, satype.item_type)
return dt.Array(value_dtype, nullable=nullable)
def test_literal_with_implicit_type(value, expected_type):
expr = ibis.literal(value)
assert isinstance(expr, ir.ScalarExpr)
assert expr.type() == dt.dtype(expected_type)
assert isinstance(expr.op(), ops.Literal)
assert expr.op().value is value
def test_zero_subtract_literal_promotions(
table, op, left_fn, right_fn, ex_type
):
# in case of zero subtract the order of operands matters
left, right = left_fn(table), right_fn(table)
result = op(left, right)
assert result.type() == dt.dtype(ex_type)
def trans_struct(t, context):
return 'STRUCT<{}>'.format(
', '.join(
'{} {}'.format(
name, ibis_type_to_bigquery_type(dt.dtype(type), context)
)
for name, type in zip(t.names, t.types)
)
)
def infer_parquet_schema(schema):
pairs = []
for field in schema.to_arrow_schema():
ibis_dtype = dt.dtype(field.type, nullable=field.nullable)
name = field.name
if not re.match(r'^__index_level_\d+__$', name):
pairs.append((name, ibis_dtype))
return sch.schema(pairs)
def shape_like(arg, dtype=None):
if isinstance(arg, (tuple, list, ir.ListExpr)):
datatype = dtype or highest_precedence_dtype(arg)
columnar = util.any_of(arg, ir.AnyColumn)
else:
datatype = dtype or arg.type()
columnar = isinstance(arg, ir.AnyColumn)
dtype = dt.dtype(datatype)
if columnar:
return dtype.column_type()
else:
return dtype.scalar_type()
def parse_type(t):
t = t.lower()
if t in _impala_to_ibis_type:
return _impala_to_ibis_type[t]
else:
if 'varchar' in t or 'char' in t:
return 'string'
elif 'decimal' in t:
result = dt.dtype(t)
if result:
return t
else:
return ValueError(t)
else:
raise Exception(t)
def value(dtype, arg):
"""Validates that the given argument is a Value with a particular datatype
Parameters
----------
dtype : DataType subclass or DataType instance
arg : python literal or an ibis expression
If a python literal is given the validator tries to coerce it to an ibis
literal.
Returns
-------
arg : AnyValue
An ibis value expression with the specified datatype
"""
if not isinstance(arg, ir.Expr):
# coerce python literal to ibis literal
arg = ir.literal(arg)
if not isinstance(arg, ir.AnyValue):
raise com.IbisTypeError(
'Given argument with type {} is not a value '
'expression'.format(type(arg))
)
# retrieve literal values for implicit cast check
value = getattr(arg.op(), 'value', None)
if isinstance(dtype, type) and isinstance(arg.type(), dtype):
# dtype class has been specified like dt.Interval or dt.Decimal
return arg
elif dt.castable(arg.type(), dt.dtype(dtype), value=value):
# dtype instance or string has been specified and arg's dtype is
# implicitly castable to it, like dt.int8 is castable to dt.int64
return arg
else:
raise com.IbisTypeError(
'Given argument with datatype {} is not '
'subtype of {} nor implicitly castable to '
'it'.format(arg.type(), dtype)
)
def test_struct():
orders = """array<struct<
oid: int64,
status: string,
totalprice: decimal(12, 2),
order_date: string,
items: array<struct<
iid: int64,
name: string,
price: decimal(12, 2),
discount_perc: decimal(12, 2),
shipdate: string
>>
>>"""
expected = dt.Array(
dt.Struct.from_tuples(
[
('oid', dt.int64),
('status', dt.string),
('totalprice', dt.Decimal(12, 2)),
('order_date', dt.string),
(
'items',
dt.Array(
dt.Struct.from_tuples(
[
('iid', dt.int64),
('name', dt.string),
('price', dt.Decimal(12, 2)),
('discount_perc', dt.Decimal(12, 2)),
('shipdate', dt.string),
]
)
),
),
]
)
)
assert dt.dtype(orders) == expected
def test_char_varchar_invalid(spec):
with pytest.raises(IbisTypeError):
dt.dtype(spec)
def literal(value, type=None):
"""Create a scalar expression from a Python value.
Parameters
----------
value : some Python basic type
A Python value
type : ibis type or string, optional
An instance of :class:`ibis.expr.datatypes.DataType` or a string
indicating the ibis type of `value`. This parameter should only be used
in cases where ibis's type inference isn't sufficient for discovering
the type of `value`.
Returns
-------
literal_value : Literal
An expression representing a literal value
Examples
--------
>>> import ibis
>>> x = ibis.literal(42)
>>> x.type()
int8
>>> y = ibis.literal(42, type='double')
>>> y.type()
float64
>>> ibis.literal('foobar', type='int64') # doctest: +ELLIPSIS
Traceback (most recent call last):
...
TypeError: Value 'foobar' cannot be safely coerced to int64
"""
import ibis.expr.datatypes as dt
import ibis.expr.operations as ops
if hasattr(value, 'op') and isinstance(value.op(), ops.Literal):
return value
try:
inferred_dtype = dt.infer(value)
except com.InputTypeError:
has_inferred = False
else:
has_inferred = True
if type is None:
has_explicit = False
else:
has_explicit = True
explicit_dtype = dt.dtype(type)
if has_explicit and has_inferred:
try:
# ensure type correctness: check that the inferred dtype is
# implicitly castable to the explicitly given dtype and value
dtype = inferred_dtype.cast(explicit_dtype, value=value)
except com.IbisTypeError:
raise TypeError(
'Value {!r} cannot be safely coerced to {}'.format(value, type)
)
elif has_explicit:
dtype = explicit_dtype
elif has_inferred:
dtype = inferred_dtype
else:
raise TypeError(
'The datatype of value {!r} cannot be inferred, try '
'passing it explicitly with the `type` keyword.'.format(value)
)
if dtype is dt.null:
return null().cast(dtype)
else:
return ops.Literal(value, dtype=dtype).to_expr()
def test_decimal_failure(case):
with pytest.raises(IbisTypeError):
dt.dtype(case)
def _grouped(input_type, output_type, base_class, output_type_method):
"""Define a user-defined function that is applied per group.
Parameters
----------
input_type : List[ibis.expr.datatypes.DataType]
A list of the types found in :mod:`~ibis.expr.datatypes`. The
length of this list must match the number of arguments to the
function. Variadic arguments are not yet supported.
output_type : ibis.expr.datatypes.DataType
The return type of the function.
base_class : Type[T]
The base class of the generated Node
output_type_method : Callable
A callable that determines the method to call to get the expression
type of the UDF
See Also
--------
ibis.pandas.udf.reduction
ibis.pandas.udf.analytic
"""
input_type = list(map(dt.dtype, input_type))
output_type = dt.dtype(output_type)
def wrapper(func):
funcsig = valid_function_signature(input_type, func)
UDAFNode = type(
func.__name__,
(base_class, ),
{
'signature': sig.TypeSignature.from_dtypes(input_type),
'output_type': output_type_method(output_type),
},
)
# An execution rule for a simple aggregate node
@execute_node.register(UDAFNode,
*udf_signature(input_type,
pin=None,
klass=pd.Series))
def execute_udaf_node(op, *args, **kwargs):
args, kwargs = arguments_from_signature(
funcsig, *args, **kwargs)
return func(*args, **kwargs)
# An execution rule for a grouped aggregation node. This
# includes aggregates applied over a window.
nargs = len(input_type)
group_by_signatures = [
udf_signature(input_type, pin=pin, klass=SeriesGroupBy)
for pin in range(nargs)
]
@toolz.compose(*(execute_node.register(UDAFNode, *types)
for types in group_by_signatures))
def execute_udaf_node_groupby(op, *args, **kwargs):
# construct a generator that yields the next group of data
# for every argument excluding the first (pandas performs
# the iteration for the first argument) for each argument
# that is a SeriesGroupBy.
#
# If the argument is not a SeriesGroupBy then keep
# repeating it until all groups are exhausted.
aggcontext = kwargs.pop('aggcontext', None)
assert aggcontext is not None, 'aggcontext is None'
if isinstance(aggcontext, Window):
# Call the func differently for Window because of
# the custom rolling logic.
result = aggcontext.agg(args[0], func, *args, **kwargs)
else:
iters = create_gens_from_args_groupby(args[1:])
funcsig = signature(func)
# TODO: Unify calling convension here to be more like
# window
def aggregator(first, *rest, **kwargs):
# map(next, *rest) gets the inputs for the next group
# TODO: might be inefficient to do this on every call
args, kwargs = arguments_from_signature(
funcsig, first, *map(next, rest), **kwargs)
return func(*args, **kwargs)
result = aggcontext.agg(args[0], aggregator, *iters,
**kwargs)
return result
@functools.wraps(func)
def wrapped(*args):
return UDAFNode(*args).to_expr()
return wrapped
return wrapper
def test_pandas_dtype(pandas_dtype, ibis_dtype):
assert dt.dtype(pandas_dtype) == ibis_dtype
def test_token_error():
with pytest.raises(IbisTypeError):
dt.dtype('array<string>>')
def test_map_does_not_allow_non_primitive_keys():
with pytest.raises(IbisTypeError):
dt.dtype('map<array<string>, double>')
def test_array():
assert dt.dtype('ARRAY<DOUBLE>') == dt.Array(dt.double)
def test_timestamp_with_timezone_parser_double_quote():
t = dt.dtype("timestamp('US/Eastern')")
assert isinstance(t, dt.Timestamp)
assert t.timezone == 'US/Eastern'
def test_char_varchar_invalid(spec):
with pytest.raises(SyntaxError):
dt.dtype(spec)
def test_primitive(spec, expected):
assert dt.dtype(spec) == expected
def test_char_varchar(spec):
assert dt.dtype(spec) == dt.string
(operator.pow, 'b', 1.5, 'double'),
(operator.pow, 'c', 1.5, 'double'),
(operator.pow, 'd', 1.5, 'double'),
(operator.pow, 'e', 2, 'float'),
(operator.pow, 'f', 2, 'double'),
(operator.pow, 'a', -2, 'double'),
(operator.pow, 'b', -2, 'double'),
(operator.pow, 'c', -2, 'double'),
(operator.pow, 'd', -2, 'double'),
],
ids=lambda arg: str(getattr(arg, '__name__', arg)))
def test_literal_promotions(table, op, name, case, ex_type):
col = table[name]
result = op(col, case)
assert result.type() == dt.dtype(ex_type)
result = op(case, col)
assert result.type() == dt.dtype(ex_type)
@pytest.mark.parametrize(('op', 'left_fn', 'right_fn', 'ex_type'), [
(operator.sub, lambda t: t['a'], lambda t: 0, 'int8'),
(operator.sub, lambda t: 0, lambda t: t['a'], 'int16'),
(operator.sub, lambda t: t['b'], lambda t: 0, 'int16'),
(operator.sub, lambda t: 0, lambda t: t['b'], 'int32'),
(operator.sub, lambda t: t['c'], lambda t: 0, 'int32'),
(operator.sub, lambda t: 0, lambda t: t['c'], 'int64'),
],
ids=lambda arg: str(getattr(arg, '__name__', arg)))
def test_zero_subtract_literal_promotions(table, op, left_fn, right_fn,
def spark_dataframe_schema(df):
"""Infer the schema of a Spark SQL `DataFrame` object."""
# df.schema is a pt.StructType
schema_struct = dt.dtype(df.schema)
return sch.schema(schema_struct.names, schema_struct.types)
def test_timestamp_with_timezone_parser_double_quote():
t = dt.dtype("timestamp('US/Eastern')")
assert isinstance(t, dt.Timestamp)
assert t.timezone == 'US/Eastern'
def test_timestamp_with_timezone_parser_invalid_timezone():
ts = dt.dtype("timestamp('US/Ea')")
assert str(ts) == "timestamp('US/Ea')"
def test_empty_complex_type():
with pytest.raises(IbisTypeError):
dt.dtype('map<>')
def test_nested_array():
assert dt.dtype('array<array<string>>') == dt.Array(dt.Array(dt.string))
def test_time_valid():
assert dt.dtype('time').equals(dt.time)
def test_interval_invalid_type():
with pytest.raises(TypeError):
dt.Interval('m', dt.float32)
with pytest.raises(TypeError):
dt.dtype("interval<float>('s')")
def test_empty_complex_type():
with pytest.raises(IbisTypeError):
dt.dtype('map<>')
def test_time_valid():
assert dt.dtype('time').equals(dt.time)
def literal(value: Any, type: dt.DataType | str | None = None) -> ScalarExpr:
"""Create a scalar expression from a Python value.
!!! tip "Use specific functions for arrays, structs and maps"
Ibis supports literal construction of arrays using the following
functions:
1. [`ibis.array`][ibis.array]
1. [`ibis.struct`][ibis.struct]
1. [`ibis.map`][ibis.map]
Constructing these types using `literal` will be deprecated in a future
release.
Parameters
----------
value
A Python value
type
An instance of [`DataType`][ibis.expr.datatypes.DataType] or a string
indicating the ibis type of `value`. This parameter can be used
in cases where ibis's type inference isn't sufficient for discovering
the type of `value`.
Returns
-------
ScalarExpr
An expression representing a literal value
Examples
--------
Construct an integer literal
>>> import ibis
>>> x = ibis.literal(42)
>>> x.type()
Int8(nullable=True)
Construct a `float64` literal from an `int`
>>> y = ibis.literal(42, type='double')
>>> y.type()
Float64(nullable=True)
Ibis checks for invalid types
>>> ibis.literal('foobar', type='int64') # doctest: +ELLIPSIS
Traceback (most recent call last):
...
TypeError: Value 'foobar' cannot be safely coerced to int64
"""
import ibis.expr.datatypes as dt
import ibis.expr.operations as ops
if hasattr(value, 'op') and isinstance(value.op(), ops.Literal):
return value
try:
inferred_dtype = dt.infer(value)
except com.InputTypeError:
has_inferred = False
else:
has_inferred = True
if type is None:
has_explicit = False
else:
has_explicit = True
explicit_dtype = dt.dtype(type)
if has_explicit and has_inferred:
try:
# ensure type correctness: check that the inferred dtype is
# implicitly castable to the explicitly given dtype and value
dtype = inferred_dtype.cast(explicit_dtype, value=value)
except com.IbisTypeError:
raise TypeError(
f'Value {value!r} cannot be safely coerced to {type}'
)
elif has_explicit:
dtype = explicit_dtype
elif has_inferred:
dtype = inferred_dtype
else:
raise TypeError(
'The datatype of value {!r} cannot be inferred, try '
'passing it explicitly with the `type` keyword.'.format(value)
)
if dtype is dt.null:
return null().cast(dtype)
else:
value = dt._normalize(dtype, value)
return ops.Literal(value, dtype=dtype).to_expr()
def test_map():
assert dt.dtype('map<string, double>') == dt.Map(dt.string, dt.double)
def test_numpy_dtype(numpy_dtype, ibis_dtype):
assert dt.dtype(np.dtype(numpy_dtype)) == ibis_dtype
def test_char_varchar_invalid(spec):
with pytest.raises(IbisTypeError):
dt.dtype(spec)
def __init__(self, input_type, output_type):
self.input_type = list(map(dt.dtype, input_type))
self.output_type = dt.dtype(output_type)
self.spark_output_type = spark_dtype(self.output_type)
def test_map_does_not_allow_non_primitive_keys():
with pytest.raises(SyntaxError):
dt.dtype('map<array<string>, double>')
def test_char_varchar(spec):
assert dt.dtype(spec) == dt.string
def test_dtype(spec, expected):
assert dt.dtype(spec) == expected
def test_primitive_from_string(spec, expected):
assert dt.dtype(spec) == expected
def infer_numpy_scalar(value):
return dt.dtype(value.dtype)
def test_timestamp_with_timezone_parser_invalid_timezone():
ts = dt.dtype("timestamp('US/Ea')")
assert str(ts) == "timestamp('US/Ea')"
def infer_array(value):
# TODO(kszucs): infer series
return dt.Array(dt.dtype(value.dtype.name))
def test_interval_invalid_type():
with pytest.raises(TypeError):
dt.Interval('m', dt.float32)
with pytest.raises(TypeError):
dt.dtype("interval<float>('s')")
def test_empty_complex_type():
with pytest.raises(parsy.ParseError):
dt.dtype('map<>')
def test_string_argument_parsing_failure_mode(case):
with pytest.raises(IbisTypeError):
dt.dtype(case)
def test_token_error():
with pytest.raises(parsy.ParseError):
dt.dtype('array<string>>')
def test_dtype(spec, expected):
assert dt.dtype(spec) == expected
def test_primitive_from_string(spec, expected):
assert dt.dtype(spec) == expected
def test_token_error():
with pytest.raises(IbisTypeError):
dt.dtype('array<string>>')
def test_char_varchar_invalid(spec):
with pytest.raises(parsy.ParseError):
dt.dtype(spec)
def test_nested_map():
expected = dt.Map(dt.int64, dt.Array(dt.Map(dt.string, dt.int8)))
assert dt.dtype('map<int64, array<map<string, int8>>>') == expected
def datatype(arg):
return dt.dtype(arg)