pytables-users

[Pytables-users] Is it possible to manipulate a VariableNode in a query?

[Aquil H. A. <aqu...@gm...>]

Hello All, 

I am querying a table that has a field with a string value. I would like to determine if the string matches a pattern. Is there a simple way to do that through readWhere and the condition syntax?  None of the following work, but I was wondering if it were possible to do something similar:

table.readWhere('"CLZ' in field') or table.readWhere('symbol[:3] == "CLZ"')

Thanks! 

-- 
Aquil H. Abdullah
"I never think of the future. It comes soon enough" - Albert Einstein

Re: [Pytables-users] Is it possible to manipulate a VariableNode in a query?

[Anthony S. <sc...@gm...>]

Hello Aquil,

Unfortunately, You currently cannot use indexing in queries (ie "symbol[:3]
== x") and may only use the whole variable ("symbol == x".  This is a
limitation of numexpr.  Please file a ticket with them, if you would like
to see this changed.  Sorry!

Be Well
Anthony

On Tue, Oct 30, 2012 at 10:44 AM, Aquil H. Abdullah <
aqu...@gm...> wrote:

>  Hello All,
>
> I am querying a table that has a field with a string value. I would like
> to determine if the string matches a pattern. Is there a simple way to do
> that through readWhere and the condition syntax?  None of the following
> work, but I was wondering if it were possible to do something similar:
>
> table.readWhere('"CLZ' in field') or table.readWhere('symbol[:3] == "CLZ"')
>
> Thanks!
>
> --
> Aquil H. Abdullah
> "I never think of the future. It comes soon enough" - Albert Einstein
>
>
>
> ------------------------------------------------------------------------------
> Everyone hates slow websites. So do we.
> Make your web apps faster with AppDynamics
> Download AppDynamics Lite for free today:
> http://p.sf.net/sfu/appdyn_sfd2d_oct
> _______________________________________________
> Pytables-users mailing list
> Pyt...@li...
> https://lists.sourceforge.net/lists/listinfo/pytables-users
>
>

Re: [Pytables-users] Is it possible to manipulate a VariableNode in a query?

[Aquil H. A. <aqu...@gm...>]

Bah! Thanks for the quick reply! 

-- 
Aquil H. Abdullah
"I never think of the future. It comes soon enough" - Albert Einstein


On Tuesday, October 30, 2012 at 10:49 AM, Anthony Scopatz wrote:

> Hello Aquil, 
> 
> Unfortunately, You currently cannot use indexing in queries (ie "symbol[:3] == x") and may only use the whole variable ("symbol == x".  This is a limitation of numexpr.  Please file a ticket with them, if you would like to see this changed.  Sorry! 
> 
> Be Well
> Anthony
> 
> On Tue, Oct 30, 2012 at 10:44 AM, Aquil H. Abdullah <aqu...@gm... (mailto:aqu...@gm...)> wrote:
> > Hello All, 
> > 
> > I am querying a table that has a field with a string value. I would like to determine if the string matches a pattern. Is there a simple way to do that through readWhere and the condition syntax?  None of the following work, but I was wondering if it were possible to do something similar: 
> > 
> > table.readWhere('"CLZ' in field') or table.readWhere('symbol[:3] == "CLZ"')
> > 
> > Thanks! 
> > 
> > -- 
> > Aquil H. Abdullah
> > "I never think of the future. It comes soon enough" - Albert Einstein
> > 
> > 
> > ------------------------------------------------------------------------------
> > Everyone hates slow websites. So do we.
> > Make your web apps faster with AppDynamics
> > Download AppDynamics Lite for free today:
> > http://p.sf.net/sfu/appdyn_sfd2d_oct
> > _______________________________________________
> > Pytables-users mailing list
> > Pyt...@li... (mailto:Pyt...@li...)
> > https://lists.sourceforge.net/lists/listinfo/pytables-users
> > 
> 
> ------------------------------------------------------------------------------
> Everyone hates slow websites. So do we.
> Make your web apps faster with AppDynamics
> Download AppDynamics Lite for free today:
> http://p.sf.net/sfu/appdyn_sfd2d_oct
> 
> _______________________________________________
> Pytables-users mailing list
> Pyt...@li... (mailto:Pyt...@li...)
> https://lists.sourceforge.net/lists/listinfo/pytables-users
> 
> 

Re: [Pytables-users] Is it possible to manipulate a VariableNode in a query?

[Francesc A. <fa...@py...>]

On 10/30/12 10:44 AM, Aquil H. Abdullah wrote:
> Hello All,
>
> I am querying a table that has a field with a string value. I would 
> like to determine if the string matches a pattern. Is there a simple 
> way to do that through readWhere and the condition syntax?  None of 
> the following work, but I was wondering if it were possible to do 
> something similar:
>
> table.readWhere('"CLZ' in field') or table.readWhere('symbol[:3] == 
> "CLZ"')

As Anthony said, there is not support for this for in-kernel (or 
indexed) queries, but you can always use a regular query for that. I.e. 
something along the lines:

np.fromiter((r for r in table if 'CLZ' in r['symbol']), dtype=table.dtype)

-- 
Francesc Alted