Hi Darryl,
Thank you very much for your quick response.

Perhaps it's my fault, the way I stored the data.
The point is, that I am looking the fastest and performant way to grab the data from a big pool.

I don't want to iterate the whole thing over and over again to get the matched entries. If i would have 100.000 - 500.000 entries, where 150 would match, I don't want to go over those completely.

So, if there is a pythonic way to get it solved on a performant way, or a ZODB way as well that would be wondefull.


Thanks a lot



Tamer


On 11.12.2013 03:56, Darryl Dixon - Winterhouse Consulting wrote:
Hi Tamer,

It depends on what you're trying to achieve. BTrees should not be mutated
whilst iterating over them, so depending on how you have structured your
data, you might do something like:

for key in [x for x in BTree.keys() if x.startswith('aa')]:
     # Do stuff

Or perhaps something else like:

for key in list(BTree.keys()):
     if key['subkey'] == 5:
         yield BTree[key]

...Or some other pattern depending on your use case.

The key here is that the ZODB really allows you to "cut out the middle
man" where previously you might store data in an RDBMS and then do
processing/transformation of that data in Python after extracting it with
SQL (and then re-storing it again afterwards), instead now you can just
directly process the data as if it was in Python objects waiting the
entire time.

Hope this helps.

regards,
Darryl Dixon
Winterhouse Consulting Ltd


Hi people!

I am working a lot with IOB and OOB Trees as well with PersistentDict
and PersistentList to store my Data in ZODB.
I want to ask if there is a way to grab data from a dataset by search
time.

I know only the SQL way:

select lower(COL1) from table1 where COL1 LIKE 'aa%'

so usually I want to get the entryies only that starts with 'aa'

do I have to iterate the entire dict with an interator or are there
builtin functions that could accomplish those tasks for me ?!


I would kindly thank you



Tamer
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