[Baypiggies] sorting a table by column

[David Berthelot]

Looks like a typical SQL problem.

If I was to solve it in Python, assuming that due to computational
time motivations the data cannot be resorted completely with:
sort(key=itemgetter(column))

Then I would keep the table unsorted and I would create an index
structure per column.
index = [[] for c in xrange(columns)]

When a row is added to the data table, I would add it to the index
lists in sorted manner using the bisect module:
row_id = len(data)
data.append(row)
for c in xrange(columns):
  bisect.insort_right(index[c],(data[row_id][c],row_id))

To lookup the table in sorted order according to column c, you would
get the table indexes:
ilist = map(itemgetter(1),index[c])
for x in ilist:
  print data[x]

I just typed this on top of my head, so it's more to give the general
principle than a robust implementation obviously.

Similarly you could implement multi-column indexes, by replacing the
tuple (data[row_id][x],row_id) with
(data[row_id][col_1],data[row_id][col_2],...,data[row_id][col_n],row_id)
assuming you desire a multi-column index on col_1,...,col_n

On Thu, Jun 23, 2011 at 6:03 AM, Tripathi, Bibha
<bibha.tripathi at jpmchase.com> 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? and which sorting method to
> make it look like real time as the user enters her choice of column to sort
> on?
>
>
>
> thanks.
>
> This communication is for informational purposes only. It is not intended as
> an offer or solicitation for the purchase or sale of any financial
> instrument or as an official confirmation of any transaction. All market
> prices, data and other information are not warranted as to completeness or
> accuracy and are subject to change without notice. Any comments or
> statements made herein do not necessarily reflect those of JPMorgan Chase &
> Co., its subsidiaries and affiliates. This transmission may contain
> information that is privileged, confidential, legally privileged, and/or
> exempt from disclosure under applicable law. If you are not the intended
> recipient, you are hereby notified that any disclosure, copying,
> distribution, or use of the information contained herein (including any
> reliance thereon) is STRICTLY PROHIBITED. Although this transmission and any
> attachments are believed to be free of any virus or other defect that might
> affect any computer system into which it is received and opened, it is the
> responsibility of the recipient to ensure that it is virus free and no
> responsibility is accepted by JPMorgan Chase & Co., its subsidiaries and
> affiliates, as applicable, for any loss or damage arising in any way from
> its use. If you received this transmission in error, please immediately
> contact the sender and destroy the material in its entirety, whether in
> electronic or hard copy format. Thank you. Please refer to
> http://www.jpmorgan.com/pages/disclosures for disclosures relating to
> European legal entities.
>
> _______________________________________________
> Baypiggies mailing list
> Baypiggies at python.org
> To change your subscription options or unsubscribe:
> http://mail.python.org/mailman/listinfo/baypiggies
>