README.md

Using Python with kdb+ (PyQ)

PyQ brings the Python programming language to the kdb+ database. It allows developers to integrate Python and q code seamlessly in one application. This is achieved by bringing the Python and q interpreters into the same process, so that code written in either of the languages operates on the same data.

In PyQ, Python and q objects live in the same memory space and share the same data.

Please report any issues in the GitHub repository.

Quick start

Install pyq:

pip install pyq

Start an interactive session:

pyq

Import the q object from pyq and the date class from the standard library module datetime:

>>> from pyq import q
>>> from datetime import date

Drop to the q) prompt and create an empty trade table:

>>> q()

q)trade:([]date:();sym:();qty:())

Get back to the Python prompt and insert some data into the trade table:

q)\

>>> q.insert('trade', (date(2006,10,6), 'IBM', 200))
k(',0')
>>> q.insert('trade', (date(2006,10,6), 'MSFT', 100))
k(',1')

(In the following we will skip q() and \ commands that switch between q and Python.)

Display the result:

>>> q.trade.show()
date       sym  qty
-------------------
2006.10.06 IBM  200
2006.10.06 MSFT 100

Define a function in q:

f:{[s;d]select from trade where sym=s,date=d}

Call the q function from Python and pretty-print the result:

>>> x = q.f('IBM', date(2006,10,6))
>>> x.show()
date       sym qty
------------------
2006.10.06 IBM 200

For an enhanced interactive shell, use the ipyq script to start IPython or the pq script to start a prompt toolkit based shell.