Convert Pythonic data to PyKX

This page documents converting python data types to PyKX data types via the pykx.toq function.

pykx.toq

pykx.toq.from_* methods should not be used directly

pykx.toq or one of the pykx.K subclassses should instead be used to convert a value into a pykx.K object. The pykx.toq.from_* functions are automatically called by these higher-level interfaces. They are documented here to explain what conversions from Python to q are supported, and how they are performed.

Converts a Python object to a pykx.K object.

pykx.toq can be called to automatically select the appropriate pykx.toq.from_* function based on the type of the provided Python object. Refer to the documentation for each of the pykx.toq.from_* functions for more details about how each conversion works.

Instead of calling e.g. pykx.toq('qwerty', ktype=pykx.CharVector), one can instantiate the desired type directly like so: pykx.CharVector('qwerty').

Examples:

>>> import pykx as kx
>>> import pandas as pd
>>> kx.toq('grok')
pykx.SymbolAtom(pykx.q('`grok'))
>>> kx.toq('grok', ktype=kx.CharVector)
pykx.CharVector(pykx.q('"grok"'))
>>> df = pd.DataFrame.from_dict({'x': [1, 2], 'y': ['a', 'b']})
>>> kx.toq(df)
pykx.Table(pykx.q('
x y
---
1 a
2 b
'))
>>> kx.toq(df, ktype={'x': kx.CharVector})
pykx.Table(pykx.q('
x    y
------
,"1" a
,"2" b
'))

Parameters:

Name	Type	Description	Default
x	Any	A Python object which is to be converted into a pykx.K object.	required
ktype	Optional[Union[pykx.K, int, dict]]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. If specified as a dictionary will convert tabular data based on mapping of column name to type. Note that dictionary based conversion is only supported when operating in licensed mode.	None
cast	bool	Cast the input Python object to the closest conforming Python type before converting to a pykx.K object.	False
`handle_nulls	bool	Convert pd.NaT to corresponding q null values in Pandas dataframes and Numpy arrays.	False

Returns:

Type	Description
pykx.K	The provided Python object as an analogous pykx.K object.

from_arrow method descriptor

from_arrow(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

See Also

• from_pandas_dataframe
• from_pandas_series

Memory usage may spike during this function.

Normally converting from Python to q results in one copy of the data being made, but because this function first converts to Pandas, it's possible for there to be a temporary third copy made. See the PyArrow docs about converting to Pandas for more details <https://arrow.apache.org/docs/python/pandas.html#memory-usage-and-zero-copy>_.

Converts PyArrow arrays/tables into PyKX vectors/tables, respectively.

Conversions from PyArrow to q are performed by converting the PyArrow array/table to pandas first, which avoids copying data when possible, then converting the resulting Pandas data structure to q using from_pandas_series or from_pandas_dataframe as appropriate.

Parameters:

Name	Type	Description	Default
x	Union['pa.Array', 'pa.Table']	The pyarrow.Array that will be converted into a pykx.Vector, or the pyarrow.Table that will be converted into a pykx.Table.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. This argument is propagated to the Pandas conversion functions (which in turn propagate it to the Numpy conversion functions).	None
cast	bool	Unused.	False
handle_nulls	bool	Unused.	False

Raises:

Type	Description
TypeError	Cannot convert PyArrow extension array to ktype.

Returns:

Type	Description
Union[k.Vector, k.Table]	An instance of pykx.Vector or pykx.Table.

from_bytes method descriptor

from_bytes(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

Converts a bytes object into an instance of a string-like subclass of pykx.K.

Parameters:

Name	Type	Description	Default
x	bytes	The bytes object that will be converted into a pykx.K object.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. The following values are supported: ktype Returned value None Same as for ktype=pykx.CharVector when len(x) != 1. Same as for ktype=pykx.CharAtom when len(x) == 1. pykx.CharVector The str as a q character vector. pykx.SymbolAtom The str as a q symbol. pykx.CharAtom The str as a q character atom.	None
cast	bool	Unused.	False
handle_nulls	bool	Unused.	False

Raises:

Type	Description
TypeError	Unsupported ktype for bytes.
ValueError	ktype=pykx.CharAtom, but x is not 1 character long.

Returns:

Type	Description
Union[k.SymbolAtom, k.SymbolVector, k.CharAtom]	An instance of a pykx.CharVector, pykx.SymbolAtom, or pykx.CharAtom.

from_callable method descriptor

from_callable(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

Inspection of the callable must be possible.

In order to determine how many parameters a provided callable has, PyKX calls inspect.signature on it. Some callables may not be introspectable in certain implementations of Python. For example, in CPython, some built-in functions defined in C provide no metadata about their arguments.

Converts a callable object into a q composition.

The resulting pykx.Composition object works by keeping a reference to the provided callable object. When the composition is called, it calls the Python callable with the arguments it received as pykx.K objects. Therefore, Python functions that are converted to q functions must be able to handle receiving pykx.K objects as arguments.

The return value of the provided Python callable will automatically be converted to a pykx.K object by having pykx.K called on it. You can control how this conversion happens by manually ensuring the return value of the function is a pykx.K instance.

Because q does not have keyword arguments, all of the parameters of the Python callable are treated as position parameters. *args and **kwargs are likewise treated as individual parameters, which can be provided a pykx.Vector and a pykx.Mapping respectively.

Functions in q can have at most 8 parameters, so Python callables being converted to q must abide by this limit. Parameters which have defaults set still count towards this limit. An *args parameters and a **kwargs each count as a single parameter towards this limit.

Parameters:

Name	Type	Description	Default
x	Callable	A callable Python object that can take pykx.K as arguments, and returns an object that can be converted into a q object via pykx.K.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. The following values are supported: ktype Returned value None Same as for ktype=pykx.Composition. pykx.Composition | A q composition that wraps the provided callable object.	None
cast	bool	Unused.	False
handle_nulls	bool	Unused.	False

Raises:

Type	Description
TypeError	Unsupported ktype for a callable object.
ValueError	x accepts too many parameters - no more than 8 can be accepted.
ValueError	inspect.signature(x) failed - could not introspect x.

Returns:

Type	Description
k.Composition	A pykx.Composition that calls the provided Python callable object when it is calls.

from_datetime_date method descriptor

from_datetime_date(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

Converts a datetime.date into an instance of a subclass of pykx.TemporalFixedAtom.

Parameters:

Name	Type	Description	Default
x	Any	The datetime.date that will be converted into a pykx.TemporalFixedAtom.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. The following values are supported: ktype Returned value None Same as for ktype=pykx.DateAtom. pykx.TimestampAtom The datetime.date as a q timestamp atom, which is a signed 64 bit value representing the number of nanoseconds since the q epoch: 2000-01-01T00:00:00.000000000. pykx.MonthAtom The datetime.date as a q month atom, which is a signed 32 bit value representing the number of months since the q epoch: 2000-01. pykx.DateAtom The datetime.date as a q date atom, which is a signed 32 bit value representing the number of days since the q epoch: 2000-01-01.	None
cast	bool	Apply a cast to a datetime.date object before converting to a pykx.TemporalFixedAtom object.	False
handle_nulls	bool	Unused.	False

Raises:

Type	Description
TypeError	Unsupported ktype for datetime.date.
NotImplementedError	The q datetime type is deprecated, so support for converting to it from Python has not been implemented.

Returns:

Type	Description
k.TemporalFixedAtom	An instance of a subclass of pykx.TemporalFixedAtom.

from_datetime_datetime method descriptor

from_datetime_datetime(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

Setting environment variable PYKX_KEEP_LOCAL_TIMES will result in the use of local time zones not UTC time.

By default this function will convert any datetime.datetime objects with time zone information to UTC before converting it to q. If you set the environment vairable to 1, true or True, then the objects with time zone information will not be converted to UTC and instead will be converted to q with no changes.

Converts a datetime.datetime into an instance of a subclass of pykx.TemporalFixedAtom.

Parameters:

Name	Type	Description	Default
x	Any	The datetime.datetime that will be converted into a pykx.TemporalFixedAtom.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. The following values are supported: ktype Returned value None Same as for ktype=pykx.TimestampAtom. pykx.TimestampAtom The datetime.datetime as a q timestamp atom, which is a signed 64 bit value representing the number of nanoseconds since the q epoch: 2000-01-01T00:00:00.000000000. pykx.MonthAtom The datetime.datetime as a q month atom, which is a signed 32 bit value representing the number of months since the q epoch: 2000-01. pykx.DateAtom The datetime.datetime as a q date atom, which is a signed 32 bit value representing the number of days since the q epoch: 2000-01-01.	None
cast	bool	Apply a cast to a datetime.datetime object before converting to a pykx.TemporalFixedAtom object.	False
handle_nulls	bool	Unused.	False

Raises:

Type	Description
TypeError	Unsupported ktype for datetime.datetime.
NotImplementedError	The q datetime type is deprecated, so support for converting to it from Python has not been implemented.

Returns:

Type	Description
k.TemporalFixedAtom	An instance of a subclass of pykx.TemporalFixedAtom.

from_datetime_timedelta method descriptor

from_datetime_timedelta(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

Converts a datetime.timedelta into an instance of a subclass of pykx.TemporalSpanAtom.

Parameters:

Name	Type	Description	Default
x	Any	The datetime.timedelta that will be converted into a pykx.TemporalSpanAtom.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. The following values are supported: ktype Returned value None Same as for ktype=pykx.TimespanAtom. pykx.TimespanAtom The datetime.timedelta as a q timespan atom, which is a signed 64 bit value representing a number of nanoseconds. pykx.MinuteAtom The datetime.timedelta as a q minute atom, which is a signed 32 bit value representing a number of minutes. pykx.SecondAtom The datetime.timedelta as a q second atom, which is a signed 32 bit value representing a number of seconds. pykx.TimeAtom The datetime.timedelta as a q date atom, which is a signed 32 bit value representing a number of milliseconds.	None
cast	bool	Apply a cast to a datetime.timedelta object before converting to a pykx.TemporalSpanAtom object.	False
handle_nulls	bool	Unused.	False

Raises:

Type	Description
TypeError	Unsupported ktype for datetime.timedelta.

Returns:

Type	Description
k.TemporalSpanAtom	An instance of a subclass of pykx.TemporalSpanAtom.

from_dict method descriptor

from_dict(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

Converts a dict into a pykx.Dictionary.

Parameters:

Name	Type	Description	Default
x	dict	The dict that will be converted into a pykx.Dictionary.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. The following values are supported: ktype Returned value None Same as for ktype=pykx.Dictionary. pykx.Dictionary The dict as a q dictionary. Each key and value of the Python dictionary will be converted independently into a pykx.K object, and added to the q dictionary.	None
cast	bool	Unused.	False
handle_nulls	bool	Convert pd.NaT to corresponding q null values in Pandas dataframes and Numpy arrays.	False

Raises:

Type	Description
TypeError	Unsupported ktype for dict.

Returns:

Type	Description
k.Dictionary	An instance of pykx.Dictionary.

from_ellipsis method descriptor

from_ellipsis(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

Projection nulls are unwieldy.

If you aren't sure you know what you are doing, then you probably don't need to use a projection null.

Converts an Ellipsis (...) into a q projection null.

PyKX uses Python's ... singleton to represent the q projection null, which is similar to generic null (see from_none), but indicates to q not just that there is missing data, but that it should be filled in with the next q object that is applied onto it.

This is how q creates function projections with later parameters specified. For instance, the q function projection {x+y}[;7] has an argument list of 2 q objects: a projection null, followed by a long atom with a value of 7.

Because PyKX treats ... as projection null, q projections can be created in Python like so:

>>> f = pykx.K(lambda x, y: x + y)
>>> projection = f(..., 7)
>>> projection(2)
pykx.LongAtom(pykx.q('9'))

Parameters:

Name	Type	Description	Default
x	Ellipsis	The Ellipsis singleton object.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. The following values are supported: ktype Returned value None Same as for ktype=pykx.ProjectionNull. pykx.ProjectionNull An instance of pykx.ProjectionNull.	None
cast	bool	Unused.	False
handle_nulls	bool	Unused.	False

Raises:

Type	Description
TypeError	Unsupported ktype for Ellipsis.

Returns:

Type	Description
k.ProjectionNull	An instance of a subclass of pykx.ProjectionNull.

from_fileno method descriptor

from_fileno(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

Converts an object with a fileno attribute to a pykx.IntAtom.

In q, int atoms that match open file descriptors can be called as if they were functions. Refer to https://code.kx.com/q/basics/handles/ for more information.

The fileno attribute of x can either be a Python int, or a function that returns an int when called. The int should represent an open file descriptor.

Parameters:

Name	Type	Description	Default
x	Any	An object with a fileno attribute.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. The following values are supported: ktype Returned value None Same as for ktype=pykx.IntAtom. pykx.IntAtom The open file descriptor as a pykx.IntAtom.	None
cast	bool	Unused.	False
handle_nulls	bool	Unused.	False

Raises:

Type	Description
TypeError	Unsupported ktype for an object with the fileno attribute.

Returns:

Type	Description
k.IntAtom	A pykx.IntAtom that represents an open file descriptor.

from_float method descriptor

from_float(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

Converts a float into an instance of a subclass of pykx.NonIntegralNumericAtom.

Parameters:

Name	Type	Description	Default
x	Any	The float that will be converted into a pykx.NonIntegralNumericAtom object.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. The following values are supported: ktype Returned value None Same as for ktype=pykx.FloatAtom. pykx.FloatAtom The float as a signed 64 bit float in q. pykx.RealAtom The float as a signed 32 bit float in q.	None
cast	bool	Apply a cast to a Python float before converting to a pykx.NonIntegralNumericAtom object.	False
handle_nulls	bool	Unused.	False

Raises:

Type	Description
TypeError	Unsupported ktype for a float.

Returns:

Type	Description
k.NonIntegralNumericAtom	An instance of a pykx.NonIntegralNumericAtom subclass.

from_int method descriptor

from_int(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

Converts an int into an instance of a subclass of pykx.IntegralNumericAtom.

Parameters:

Name	Type	Description	Default
x	Any	The int that will be converted into a pykx.IntegralNumericAtom object.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. The following values are supported: ktype Returned value None Same as for ktype=pykx.LongAtom, except when x is a bool, in which case it is the same as for ktype=pykx.BooleanAtom. pykx.LongAtom The int as a signed 64 bit integer in q. pykx.IntAtom The int as a signed 32 bit integer in q. pykx.ShortAtom The int as a signed 16 bit integer in q. pykx.ByteAtom The int as a unsigned 8 bit integer in q. pykx.BooleanAtom The int as a boolean in q.	None
cast	bool	Apply cast to Python int before converting to an pykx.IntegralNumericAtom object.	False
handle_nulls	bool	Unused.	False

Raises:

Type	Description
TypeError	Unsupported ktype for an int or unsupported cast between Python types.
OverflowError	The provided int is out of bounds for the selected pykx.IntegralNumericAtom subclass.

The edges of the bounds have special meanings in q.

For pykx.LongAtom, pykx.IntAtom, and pykx.ShortAtom, the lower bound of the range is the null value for that type, one larger than that is the negative infinity for that type, and the upper bound of the range is positive infinity for that type. An exception will not be raised if int objects with these values are provided. Refer to the nulls and infinities PyKX documentation for more information about q nulls and infinities, and how to handle them with PyKX.

Returns:

Type	Description
k.IntegralNumericAtom	An instance of a pykx.IntegralNumericAtom subclass.

from_list method descriptor

from_list(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

q lists are vectors

In q, a list (also called a "general list") is a vector of k objects. Non-list vectors (also called "typed vectors" or simply "vectors") are vectors of one particular type.

Converts a list into an instance of a subclass of pykx.Vector.

Parameters:

Name	Type	Description	Default
x	list	The list that will be converted into a pykx.Vector.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. The following values are supported: ktype Returned value None Same as for ktype=pykx.List. pykx.List The list as a q list. Each element of the Python list will be converted independently into a pykx.K object, and added to the q list. pykx.BooleanVector The list as a pykx.BooleanVector. This is equivalent to converting a Numpy array array(x, dtype=bool) to q. pykx.ByteVector The list as a pykx.ByteVector. This is equivalent to converting a Numpy array array(x, dtype=np.uint8) to q. pykx.ShortVector The list as a pykx.ShortVector. This is equivalent to converting a Numpy array array(x, dtype=np.int16) to q. pykx.IntVector The list as a pykx.IntVector. This is equivalent to converting a Numpy array array(x, dtype=np.int32) to q. pykx.LongVector The list as a pykx.LongVector. This is equivalent to converting a Numpy array array(x, dtype=np.int64) to q. pykx.RealVector The list as a pykx.RealVector. This is equivalent to converting a Numpy array array(x, dtype=np.float32) to q. pykx.FloatVector The list as a pykx.FloatVector. This is equivalent to converting a Numpy array array(x, dtype=np.float64) to q.	None
cast	bool	Unused.	False
handle_nulls	bool	Unused.	False

Raises:

Type	Description
TypeError	Unsupported ktype for list.
ValueError	Could not convert some elements of x in accordance with the ktype.

Returns:

Type	Description
k.Vector	An instance of a subclass of pykx.Vector.

from_none method descriptor

from_none(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

Converts None into a pykx.Identity object.

Parameters:

Name	Type	Description	Default
x	None	The None singleton object.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. The following values are supported: ktype Returned value None Same as for ktype=pykx.Identity. pykx.Identity Generic null (::).	None
cast	bool	Unused.	False
handle_nulls	bool	Unused.	False

Returns:

Type	Description
k.Identity	A pykx.Identity instance, i.e. generic null.

from_numpy_datetime64 method descriptor

from_numpy_datetime64(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

Converts a numpy.datetime64 into an instance of a subclass of pykx.TemporalFixedAtom.

Parameters:

Name	Type	Description	Default
x	np.datetime64	The numpy.datetime64 that will be converted into a pykx.TemporalFixedAtom.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. The following values are supported: ktype Returned value None Same as for ktype=pykx.TimestampAtom. pykx.TimestampAtom The numpy.datetime64 as a q timestamp atom, which is a signed 64 bit value representing the number of nanoseconds since the q epoch: 2000-01-01T00:00:00.000000000. pykx.MonthAtom The numpy.datetime64 as a q month atom, which is a signed 32 bit value representing the number of months since the q epoch: 2000-01. pykx.DateAtom The numpy.datetime64 as a q date atom, which is a signed 32 bit value representing the number of days since the q epoch: 2000-01-01.	None
cast	bool	Unused.	False
handle_nulls	bool	Unused.	False

Raises:

Type	Description
TypeError	Unsupported ktype for numpy.datetime64.
NotImplementedError	The q datetime type is deprecated, so support for converting to it from Python has not been implemented.

Returns:

Type	Description
k.TemporalFixedAtom	An instance of a subclass of pykx.TemporalFixedAtom.

from_numpy_ndarray method descriptor

from_numpy_ndarray(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

Data is always copied when converting from Numpy to q if not using the PyKX Allocator.

While many conversions from q to Python types can be performed without incurring a copy, the reverse is not true. As mentioned in the q C API documentation, vectors in q store their metadata in a fixed memory location relative to their data, so the data for an array in Python's memory cannot be shared by q, since q would have to store the metadata in a memory location it has no ownership of.

Converts a numpy.ndarray into a pykx.Vector.

If the pykx.k_allocator is enabled with the environment variable PYKX_ALLOCATOR or if the QARGS environment variable contains --pykxalloc, then 0 copy numpy array conversions will be enabled for certain numpy.dtypess. This will allow for 0 copy conversions from numpy arrays of a corresponding numpy.dtype to pykx.NumericVectors, and pykx.TimespanVectors. You can find the corresponding numpy.dtype of a pykx.Vector type by checking the pykx.Vector._np_dtype property of the type you want to create. Note that when these 0 copy conversions are done both the numpy array and the resulting pykx.Vector refer to the same area of memory and changes made to one will be present in the other object.

Because q only supports 1-dimensional arrays (vectors), Numpy arrays with more than 1 dimension will have all every level converted into a list of lists except for the lowest, for which each vector is converted to a q vector independently.

For example, in the following case, even though Numpy stores all of the data contiguously in memory with a single numpy.ndarray object wrapping it, q will store it as 3 vectors, with a list containing them:

>>> np.arange(12).reshape(3, 4)
array([[ 0,  1,  2,  3],
        [ 4,  5,  6,  7],
        [ 8,  9, 10, 11]])
>>> kx.K(np.arange(12).reshape(3, 4))
pykx.List(pykx.q('
0 1 2  3
4 5 6  7
8 9 10 11
'))

Numpy masked arrays can be used to indicate null data for integer types.

Parameters:

Name	Type	Description	Default
x	np.ndarray	The numpy.ndarray that will be converted into a pykx.Vector.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. The following values are supported: ktype Returned value None The returned vector is as if the ktype had been set based off of the Numpy dtype, roughly following this mapping: x.dtype Inferred ktype object pykx.List object (uuid.UUID) pykx.GUIDVector object (str) pykx.SymbolVector 'U' pykx.SymbolVector 'S' pykx.CharVector np.float64 pykx.FloatVector np.float32 pykx.RealVector np.int64 pykx.LongVector np.int32 pykx.IntVector np.int16 pykx.ShortVector 'timedelta64[ms]' pykx.TimeVector 'timedelta64[ns]' pykx.TimespanVector 'datetime64[ns]' pykx.TimestampVector 'datetime64[us]' pykx.TimestampVector 'datetime64[ms]' pykx.TimestampVector 'datetime64[s]' pykx.TimestampVector 'timedelta64[s]' pykx.SecondVector 'datetime64[M]' pykx.MonthVector 'datetime64[D]' pykx.DateVector 'timedelta64[m]' pykx.MinuteVector np.uint8 pykx.ByteVector bool pykx.BooleanVector pykx.List The Numpy array as a q general list. Equivalent to pykx.List(x.tolist()). pykx.BooleanVector The Numpy array as a vector of q booleans, which each take up 8 bits in memory. pykx.ByteVector The Numpy array as a vector of q unsigned 8 bit intergers. pykx.GUIDVector The Numpy array as a vector of q GUIDs, which each take up 128 bits in memory. pykx.ShortVector The Numpy array as a vector of q signed 16 bit integers. pykx.IntVector The Numpy array as a vector of q signed 32 bit integers. pykx.LongVector The Numpy array as a vector of q signed 64 bit integers. pykx.RealVector The Numpy array as a vector of q 32 bit floats. pykx.FloatVector The Numpy array as a vector of q 64 bit floats. pykx.CharVector The Numpy array as a vector of q characters. Each characters in q is a single byte, which has implications for multi-byte characters in e.g. Unicode strings. pykx.SymbolVector The Numpy array as a vector of q symbols. Each symbol is permanently interned into q's memory. pykx.TimestampVector The Numpy array as a vector of q timestamp, i.e. signed 64 bit integers which represent the number of nanoseconds since the q epoch: 2000-01-01T00:00:00.000000000. The data from the Numpy array will be incremented to adjust its epoch from the standard epoch (1970-01-01T00:00:00.000000000) to the q epoch. pykx.MonthVector The Numpy array as a vector of q months, i.e. signed 32 bit intergers which represent the number of months since the q epoch: 2000-01. The data from the Numpy array will be incremented to adjust its epoch from the standard epoch (1970-01) to the q epoch. pykx.DateVector The Numpy array as a vector of q dates, i.e. signed 32 bit intergers which represent the number of days since the q epoch: 2000-01-01. The data from the Numpy array will be incremented to adjust its epoch from the standard epoch (1970-01-01) to the q epoch. pykx.TimespanVector The Numpy array as a vector of q timespans, i.e. signed 64 bit integers which represent a number of nanoseconds. pykx.MinuteVector The Numpy array as a vector of q minutes, i.e. signed 32 bit integers which represent a number of minutes. pykx.SecondVector The Numpy array as a vector of q seconds, i.e. signed 32 bit integers which represent a number of seconds. pykx.TimeVector The Numpy array as a vector of q times, i.e. signed 32 bit integers which represent a number of milliseconds.	None
cast	bool	Apply a cast before converting to a pykx.Vector object. It will try to cast the input Numpy array to the Numpy type which best conforms to the target ktype.	False
handle_nulls	bool	Convert pd.NaT to corresponding q null values in Pandas dataframes and Numpy arrays.	False

Raises:

Type	Description
TypeError	Unsupported ktype for numpy.ndarray.
ValueError	Numpy array is not C-contiguous, which is required for ktype.

Returns:

Type	Description
k.Vector	An instance of a subclass of pykx.Vector.

from_numpy_timedelta64 method descriptor

from_numpy_timedelta64(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

Converts a numpy.timedelta64 into an instance of a subclass of pykx.TemporalSpanAtom.

Parameters:

Name	Type	Description	Default
x	np.timedelta64	The numpy.timedelta64 that will be converted into a pykx.TemporalSpanAtom.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. The following values are supported: ktype Returned value None Same as for ktype=pykx.TimespanAtom. pykx.TimespanAtom The numpy.timedelta64 as a q timespan atom, which is a signed 64 bit value representing a number of nanoseconds. pykx.MinuteAtom The numpy.timedelta64 as a q minute atom, which is a signed 32 bit value representing a number of minutes. pykx.SecondAtom The numpy.timedelta64 as a q second atom, which is a signed 32 bit value representing a number of seconds. pykx.TimeAtom The numpy.timedelta64 as a q time atom, which is a signed 32 bit value representing a number of milliseconds.	None
cast	bool	Unused.	False
handle_nulls	bool	Unused.	False

Raises:

Type	Description
TypeError	Unsupported ktype for numpy.timedelta64.

Returns:

Type	Description
k.TemporalSpanAtom	An instance of a subclass of pykx.TemporalSpanAtom.

from_pandas_dataframe method descriptor

from_pandas_dataframe(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

See Also

• from_pandas_index
• from_pandas_series

Converts a pandas.DataFrame into a pykx.Table or pykx.KeyedTable as appropriate.

The index and columns of the dataframe are each converted independently, and then the results of those conversions are used to assemble the resulting q table or keyed table.

If the dataframe does not have column names they will be generated: x, x1, .., x(n-1).

Parameters:

Name	Type	Description	Default
x	pd.DataFrame	The pandas.DataFrame that will be converted into a pykx.Table or pykx.KeyedTable.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. The following values are supported: ktype Returned value None The returned value is as if the ktype had been set based off of the index of the dataframe. If the index has an integer type, starts at 0, and increases by 1 for every row, then a pykx.Table is returned. Otherwise, a pykx.KeyedTable is returned. Note that pykx.KeyedTable is a subclass of pykx.Dictionary, not pykx.Table. Both are subclasses of pykx.Mapping. pykx.Table The pandas.DataFrame as a q table. pykx.KeyedTable The pandas.DataFrame as a q keyed table.	None
cast	bool	Unused.	False
handle_nulls	bool	Convert pd.NaT to corresponding q null values in Pandas dataframes and Numpy arrays.	False

Raises:

Type	Description
TypeError	Unsupported ktype for pandas.DataFrame.

Returns:

Type	Description
Union[k.Table, k.KeyedTable]	An instance of pykx.Table or pykx.KeyedTable.

from_pandas_index method descriptor

from_pandas_index(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

See Also

from_numpy_ndarray

Converts a pandas.Index into a pykx.Vector or pykx.Table as appropriate.

Parameters:

Name	Type	Description	Default
x	pd.Index	The pandas.Index that will be converted into a pykx.Table or pykx.KeyedTable.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. The following values are supported: ktype Returned value None The resulting value is determined based on the kind of Pandas index provided. If x is an instance of pandas.core.indexes.numeric.NumericIndex, then it will be converted into a Numpy array, then that will be converted into a pykx.Vector via from_numpy_ndarray. If x is an instance of pandas.MultiIndex, then each of its levels will be converted into a Numpy array, and assembled into a pykx.Table with column names equal to the names of the levels of the index if they are named. For any level which is not named, its index within x.levels is used as its name.	None
cast	bool	Unused.	False
handle_nulls	bool	Convert pd.NaT to corresponding q null values in Pandas dataframes and Numpy arrays.	False

Raises:

Type	Description
TypeError	Unsupported ktype for pandas.Index.

Returns:

Type	Description
Union[k.Vector, k.Table]	An instance of pykx.Vector or pykx.Table.

from_pandas_series method descriptor

from_pandas_series(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

See Also

from_numpy_ndarray

Converts a pandas.Series into an instance of a subclass of pykx.Vector.

The given series is converted to a Numpy array, and then converted to a q vector as Numpy arrays generally are.

Parameters:

Name	Type	Description	Default
x	pd.Series	The pandas.Series that will be converted into a pykx.Vector.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x using the same logic as from_numpy_ndarray applied to x.to_numpy().	None
cast	bool	Unused.	False
handle_nulls	bool	Convert pd.NaT to corresponding q null values in Pandas dataframes and Numpy arrays.	False

Raises:

Type	Description
TypeError	Unsupported ktype for pandas.Series.

Returns:

Type	Description
k.Vector	An instance of a subclass of pykx.Vector.

from_pathlib_path method descriptor

from_pathlib_path(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

Converts a pathlib.Path into a q handle symbol.

In q a symbol atom that begin with a : is known as an "hsym", or handle symbol. These symbols represent local or remote paths or resources.

Windows paths are reformatted as POSIX paths.

This function does not make the path absolute.

Parameters:

Name	Type	Description	Default
x	Path	The pathlib.Path that will be converted into an hsym.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. The following values are supported: ktype Returned value None Same as for ktype=pykx.SymbolAtom. pykx.SymbolAtom The pathlib.Path as a q handle symbol, which will be the path as text, prefixed by :, as a POSIX path.	None
cast	bool	Unused.	False
handle_nulls	bool	Unused.	False

Raises:

Type	Description
TypeError	Unsupported ktype for pathlib.Path.

Returns:

Type	Description
k.SymbolAtom	An instance of a subclass of pykx.IntegralNumericVector.

from_pykx_k method descriptor

from_pykx_k(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

Converts a pykx.K object into a pykx.K object.

Parameters:

Name	Type	Description	Default
x	k.K	A pykx.K instance.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. The following values are supported: ktype Returned value None The provided pykx.K object unchanged. The type ofx` Same as for ktype=None. pykx.List The provided pykx.K object as a pykx.List object pykx.BooleanAtom The provided pykx.K object as a pykx.BooleanAtom pykx.ByteAtom The provided pykx.K object as a pykx.ByteAtom pykx.ShortAtom The provided pykx.K object as a pykx.ShortAtom pykx.IntAtom The provided pykx.K object as a pykx.IntAtom pykx.LongAtom The provided pykx.K object as a pykx.LongAtom pykx.RealAtom The provided pykx.K object as a pykx.RealAtom pykx.FloatAtom The provided pykx.K object as a pykx.FloatAtom pykx.CharAtom The provided pykx.K object as a pykx.CharAtom pykx.SymbolAtom The provided pykx.K object as a pykx.SymbolAtom pykx.TimestampAtom The provided pykx.K object as a pykx.TimestampAtom pykx.MonthAtom The provided pykx.K object as a pykx.MonthAtom pykx.DateAtom The provided pykx.K object as a pykx.DateAtom pykx.DatetimeAtom The provided pykx.K object as a pykx.DatetimeAtom pykx.TimespanAtom The provided pykx.K object as a pykx.TimespanAtom pykx.MinuteAtom The provided pykx.K object as a pykx.MinuteAtom pykx.SecondAtom The provided pykx.K object as a pykx.SecondAtom pykx.TimeAtom The provided pykx.K object as a pykx.TimeAtom pykx.BooleanVector The provided pykx.K object as a pykx.BooleanVector pykx.ByteVector The provided pykx.K object as a pykx.ByteVector pykx.ShortVector The provided pykx.K object as a pykx.ShortVector pykx.IntVector The provided pykx.K object as a pykx.IntVector pykx.LongVector The provided pykx.K object as a pykx.LongVector pykx.RealVector The provided pykx.K object as a pykx.RealVector pykx.FloatVector The provided pykx.K object as a pykx.FloatVector pykx.CharVector The provided pykx.K object as a pykx.CharVector pykx.SymbolVector The provided pykx.K object as a pykx.SymbolVector pykx.TimestampVector The provided pykx.K object as a pykx.TimestampVector pykx.MonthVector The provided pykx.K object as a pykx.MonthVector pykx.DateVector The provided pykx.K object as a pykx.DateVector pykx.DatetimeVector The provided pykx.K object as a pykx.DatetimeVector pykx.TimespanVector The provided pykx.K object as a pykx.TimespanVector pykx.MinuteVector The provided pykx.K object as a pykx.MinuteVector pykx.SecondVector The provided pykx.K object as a pykx.SecondVector pykx.TimeVector The provided pykx.K object as a pykx.TimeVector pykx.Table The provided pykx.K object as a pykx.Table pykx.Dictionary The provided pykx.K object as a pykx.Dictionary	None
cast	bool	Unused.	False
handle_nulls	bool	Unused.	False

Raises:

Type	Description
LicenseException	Directly casting between ktypes is not possible without a license.
TypeError	ktype is not None and does not match the provided pykx.K object or any of the castable ktypes.
QError	Cannot cast the provided pykx.K object to ktype.

Returns:

Type	Description
k.K	The provided pykx.K instance.

from_range method descriptor

from_range(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

Converts a range into an instance of a subclass of pykx.IntegralNumericVector.

Parameters:

Name	Type	Description	Default
x	range	The range that will be converted into a pykx.IntegralNumericVector.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. The following values are supported: ktype Returned value None Same as for ktype=pykx.LongVector. pykx.LongVector The slice as a q vector of signed 64 bit integers. pykx.IntVector The slice as a q vector of signed 32 bit integers. pykx.ShortVector The slice as a q vector of signed 16 bit integers. pykx.ByteVector The slice as a q vector of unsigned 8 bit integers. pykx.BooleanVector The slice as a q vector of unsigned 1 bit integers.	None
cast	bool	Unused.	False
handle_nulls	bool	Unused.	False

Raises:

Type	Description
TypeError	Unsupported ktype for range.
OverflowError	The minimum or maximum value in the range is out of bounds for the selected ktype.

Returns:

Type	Description
k.IntegralNumericVector	An instance of a subclass of pykx.IntegralNumericVector.

from_slice method descriptor

from_slice(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

Converts a slice into an instance of a subclass of pykx.IntegralNumericVector.

Slice objects are used by Python for indexing. In q, indexing is done by applying a numeric atom or vector to the object being indexed. As such, from_slice works by converting the given slice into a pykx.IntegralNumericVector, which can then be applied to an indexable q object.

Parameters:

Name	Type	Description	Default
x	slice	The slice that will be converted into a pykx.IntegralNumericVector.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. The following values are supported: ktype Returned value None Same as for ktype=pykx.LongVector. pykx.LongVector The slice as a q vector of signed 64 bit integers. pykx.IntVector The slice as a q vector of signed 32 bit integers. pykx.ShortVector The slice as a q vector of signed 16 bit integers. pykx.ByteVector The slice as a q vector of unsigned 8 bit integers. pykx.BooleanVector The slice as a q vector of unsigned 1 bit integers.	None
cast	bool	Unused.	False
handle_nulls	bool	Unused.	False

Raises:

Type	Description
TypeError	Unsupported ktype for slice.
OverflowError	The minimum or maximum value in the slice is out of bounds for the selected ktype.

Returns:

Type	Description
k.IntegralNumericVector	An instance of a subclass of pykx.IntegralNumericVector.

from_str method descriptor

from_str(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

Converts a str into an instance of a string-like subclass of pykx.K.

Parameters:

Name	Type	Description	Default
x	str	The str that will be converted into a pykx.K object.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. The following values are supported: ktype Returned value None Same as for ktype=pykx.SymbolAtom. pykx.SymbolAtom The str as a q symbol. pykx.SymbolicFunction The str as a q symbol that can be called as a function. pykx.CharVector The str as a q character vector. pykx.CharAtom The str as a q character atom.	None
cast	bool	Unused.	False
handle_nulls	bool	Unused.	False

Raises:

Type	Description
TypeError	Unsupported ktype for a str.
ValueError	ktype=pykx.CharAtom, but x is not 1 character long.

Returns:

Type	Description
Union[k.CharAtom, k.CharVector, k.SymbolAtom]	An instance of a pykx.SymbolAtom, pykx.CharVector, or pykx.CharAtom.

from_tuple method descriptor

from_tuple(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

See Also

from_list

Converts a tuple into an instance of a subclass of pykx.Vector.

Parameters:

Name	Type	Description	Default
x	tuple	The tuple that will be converted into a pykx.Vector.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. The following values are supported: ktype Returned value None Same as for ktype=pykx.List. pykx.List The tuple as a q list. Each element of the Python list will be converted independently into a pykx.K object, and added to the q list. pykx.BooleanVector The tuple as a pykx.BooleanVector. This is equivalent to converting a Numpy array array(x, dtype=bool) to q. pykx.ByteVector The tuple as a pykx.ByteVector. This is equivalent to converting a Numpy array array(x, dtype=np.uint8) to q. pykx.ShortVector The tuple as a pykx.ShortVector. This is equivalent to converting a Numpy array array(x, dtype=np.int16) to q. pykx.IntVector The tuple as a pykx.IntVector. This is equivalent to converting a Numpy array array(x, dtype=np.int32) to q. pykx.LongVector The tuple as a pykx.LongVector. This is equivalent to converting a Numpy array array(x, dtype=np.int64) to q. pykx.RealVector The tuple as a pykx.RealVector. This is equivalent to converting a Numpy array array(x, dtype=np.float32) to q. pykx.FloatVector The tuple as a pykx.FloatVector. This is equivalent to converting a Numpy array array(x, dtype=np.float64) to q.	None
cast	bool	Unused.	False
handle_nulls	bool	Unused.	False

Raises:

Type	Description
TypeError	Unsupported ktype for tuple.
ValueError	Could not convert some elements of x in accordance with the ktype.

Returns:

Type	Description
k.Vector	An instance of a subclass of pykx.Vector.

from_uuid_UUID method descriptor

from_uuid_UUID(
    x, ktype=None, *, cast=False, handle_nulls=False, strings_as_char=False
)

Converts a uuid.UUID into a pykx.GUIDAtom.

Parameters:

Name	Type	Description	Default
x	UUID	The uuid.UUID that will be converted into a pykx.GUIDAtom.	required
ktype	Optional[KType]	Desired pykx.K subclass (or type number) for the returned value. If None, the type is inferred from x. The following values are supported: ktype Returned value None Same as for ktype=pykx.GUIDAtom. pykx.GUIDAtom The uuid.UUID as a q GUID atom.	None
cast	bool	Unused.	False
handle_nulls	bool	Unused.	False

Raises:

Type	Description
TypeError	Unsupported ktype for uuid.UUID.

Returns:

Type	Description
k.GUIDAtom	An instance of pykx.GUIDAtom.