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Differences and upgrade considerations from embedPy

As outlined here PyKX provides users with the ability to execute Python code within a q session similar to embedPy. This document outlines points of consideration when upgrading from embedPy to PyKX under q both with respect to the function mappings between the two interfaces and differences in their behavior.

Functional differences

q symbol and string support

EmbedPy does not allow users to discern between q string and symbol types when converting to Python. In both cases these are converted to str objects in Python. As a result round trip conversions are not supported in embedPy for symbols, PyKX does support such round trip operations:


Python object type support

EmbedPy contains a fundamental limitation with respect to the data formats that are supported when converting between q and Python. Namely that all q objects when passed to Python functions use the analogous Python/Numpy representation. This limitation means that a user of embedPy must handle their own data conversions when handling Pandas or PyArrow objects.

PyKX natively supports data conversions from q to Python, Numpy, Pandas and PyArrow and as such can support workflows which previously required users to manually control these conversions, for example:

q).pykx.print .pykx.eval["lambda x:type(x)"] .pykx.topd ([]10?1f)

Functionality mapping

The following table describes the function mapping from PyKX to embedPy for various elements of the supported functionality within embedPy, where a mapping supported this will be explicitly noted. Where workarounds exist these are additionally noted.

Description PyKX embedPy
Library loading \l pykx.q \l p.q
Importing Python Libraries as wrapped Python objects .pykx.import .p.import
Setting objects in Python Memory .pykx.set .p.set
Retrieving Python objects from Memory .pykx.get .p.get
Converting Python objects to q .pykx.toq .p.py2q
Execute Python code returning as intermediary q/Python object .pykx.eval .p.eval
Execute Python code returning a q object .pykx.qeval .p.qeval
Execute Python code returning a Python foreign object .pykx.pyeval .p.eval
Retrieve a printable representation of a supplied PyKX/q object .pykx.repr .p.repr
Set an attribute on a supplied Python object .pykx.setattr .p.setattr
Retrieve an attribute from a supplied Python object .pykx.getattr .p.getattr
Convert a Python foreign object to a wrapped object for conversion .pykx.wrap .p.wrap
Convert a wrapped Python object to a Python foreign object .pykx.unwrap .p.unwrap
Print a Python object to standard out .pykx.print .p.print
Import a Python library as a Python foreign object .pykx.pyimport .p.pyimport
Generate a callable Python function returning a Python foreign object .pykx.pycallable .p.pycallable
Generate a callable Python function returning a q result .pykx.qcallable .p.qcallable
Interactive Python help string Unsupported
Retrieval of Python help string as a q string Unsupported .p.helpstr
Convert a q object to a Python foreign object Unsupported .p.q2py
Create a Python closure using a q function Unsupported .p.closure
Create a Python generator using a q function Unsupported .p.generator