[Baypiggies] sorting a table by column

Bibha Tripathi tbibha at gmail.com
Fri Jun 24 07:40:02 CEST 2011

Has anyone used PYNQ? how does it perform compared with dict seart?


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On 23 Jun 2011, at 06:31 PM, Chris Clark <Chris.Clark at ingres.com> wrote:

> Tripathi, Bibha wrote:
>> a huge table like an excel sheet, saved and accumulating more data more rows, may be more tables
>> user chooses which column to sort on
>> what's the best python data structure to use?
> It probably depends on what "huge" means. If the "table" data fits in memory (either physical or virtual) it probably isn't that big and doing operations in Python (e.g. using list comprehension) is probably appropriate. If it doesn't fit in memory you can't easily use list comprehension and need to look into loops and generators, see http://danielrech.net/2011/python-generators-presentation-by-david-beazley/ (I think Alex might have done something similar at PyCon a few years ago too).
> There are some third party libs on PyPi that are worth checking out. I keep wanting to find an excuse to kick the tires on http://pypi.python.org/pypi/blist/ but I've not had cause to do so yet. Search PyPi for "tree" and there are a lot of hits.
> You can even use good old Schwartzian transforms (aka decorate-sort-undecorate) to handle changes in columns if for some reason there isn't a key argument to sort() provided by the structure you choose.
> David Berthelot wrote:
>> Looks like a typical SQL problem.
> Agreed, without more information this sounds like a classic "ORDERY BY" clause on a SELECT statement. Relational database really excel, lower case "e", rather than upper case "E" :-), at this sort of thing..... If you check my email address domain name, of course I'm going to say that ;-) Databases do a lot of the heavy lifting for you.
> If you're doing some sort of BI analytics a database is probably your best bet (I'm taking a guess you are based on your email address domain name). Shameless promotion, take a gander at http://www.thevirtualcircle.com/2011/02/vectorwise-theres-a-disturbance-in-the-force/ and http://www.ingres.com/products/vectorwise (I don't work on Vectorwise but I'm always blown away at how fast it is). If you are avoiding a traditional DBMS for performance reasons VW may well surprise you..
> Chris
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