pytables-users

[Pytables-users] iterate over specific Tables

[Uwe M. <uwe...@df...>]

Hi,

I have several leaf nodes of the same table dtype:

class VideoNode(tables.IsDescription):
    ...

Not all tables in the hdf5 file are of the same type, however. How do I iterate
over all leafes which are tables of the above class, while ignoring tables with
different signatures?

i.e. I'd like to write something like:
<code>
f = tables.openFile(...)
foo = f.walkNodes('/', classname='VideoNode')
</code>
which does not work because only the class name is "Table"...

or
<code>
bar = filter(isinstance(x, VideoNode) for x in f.walkNodes('/', 'Table')))
</code>

which does not work, because x is never an instance of VideoNode.

Any ideas?

Thanks in advance
Uwe

Re: [Pytables-users] iterate over specific Tables

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

Hello Uwe,

Why don't you try something like:

bar = filter(x.description == VideoNode for x in f.walkNodes('/', 'Table'))

or

bar = filter(x.dtype == VideoNode._v_dtype for x in f.walkNodes('/',
'Table'))

to compare the dtype / description directly?

Be Well
Anthony
On May 18, 2012 8:00 AM, "Uwe Mayer" <uwe...@df...> wrote:

> Hi,
>
> I have several leaf nodes of the same table dtype:
>
> class VideoNode(tables.IsDescription):
>    ...
>
> Not all tables in the hdf5 file are of the same type, however. How do I
> iterate
> over all leafes which are tables of the above class, while ignoring tables
> with
> different signatures?
>
> i.e. I'd like to write something like:
> <code>
> f = tables.openFile(...)
> foo = f.walkNodes('/', classname='VideoNode')
> </code>
> which does not work because only the class name is "Table"...
>
> or
> <code>
> bar = filter(isinstance(x, VideoNode) for x in f.walkNodes('/', 'Table')))
> </code>
>
> which does not work, because x is never an instance of VideoNode.
>
> Any ideas?
>
> Thanks in advance
> Uwe
>
>
>
> ------------------------------------------------------------------------------
> Live Security Virtual Conference
> Exclusive live event will cover all the ways today's security and
> threat landscape has changed and how IT managers can respond. Discussions
> will include endpoint security, mobile security and the latest in malware
> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
> _______________________________________________
> Pytables-users mailing list
> Pyt...@li...
> https://lists.sourceforge.net/lists/listinfo/pytables-users
>

Re: [Pytables-users] iterate over specific Tables

[Uwe M. <uwe...@df...>]

Hi Anthony,

On 05/19/2012 08:12 PM, Anthony Scopatz wrote:
> Why don't you try something like:
>
> bar = filter(x.description == VideoNode for x in f.walkNodes('/', 'Table'))
>
> or
>
> bar = filter(x.dtype == VideoNode._v_dtype for x in f.walkNodes('/',
> 'Table'))
>
> to compare the dtype / description directly?

Oh. *g*
This is exactly what I was looking for. I did not know how to use the 
class in a comparison for this.

Thank you!
Uwe

> On May 18, 2012 8:00 AM, "Uwe Mayer" <uwe...@df...
> <mailto:uwe...@df...>> wrote:
>
>     Hi,
>
>     I have several leaf nodes of the same table dtype:
>
>     class VideoNode(tables.IsDescription):
>         ...
>
>     Not all tables in the hdf5 file are of the same type, however. How
>     do I iterate
>     over all leafes which are tables of the above class, while ignoring
>     tables with
>     different signatures?
>
>     i.e. I'd like to write something like:
>     <code>
>     f = tables.openFile(...)
>     foo = f.walkNodes('/', classname='VideoNode')
>     </code>
>     which does not work because only the class name is "Table"...
>
>     or
>     <code>
>     bar = filter(isinstance(x, VideoNode) for x in f.walkNodes('/',
>     'Table')))
>     </code>
>
>     which does not work, because x is never an instance of VideoNode.
>
>     Any ideas?
>
>     Thanks in advance
>     Uwe
>
>
>     ------------------------------------------------------------------------------
>     Live Security Virtual Conference
>     Exclusive live event will cover all the ways today's security and
>     threat landscape has changed and how IT managers can respond.
>     Discussions
>     will include endpoint security, mobile security and the latest in
>     malware
>     threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
>     _______________________________________________
>     Pytables-users mailing list
>     Pyt...@li...
>     <mailto:Pyt...@li...>
>     https://lists.sourceforge.net/lists/listinfo/pytables-users
>
>
>
> ------------------------------------------------------------------------------
> Live Security Virtual Conference
> Exclusive live event will cover all the ways today's security and
> threat landscape has changed and how IT managers can respond. Discussions
> will include endpoint security, mobile security and the latest in malware
> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
>
>
>
> _______________________________________________
> Pytables-users mailing list
> Pyt...@li...
> https://lists.sourceforge.net/lists/listinfo/pytables-users

Re: [Pytables-users] iterate over specific Tables

[Uwe M. <uwe...@df...>]

Hi Anthony,

On 05/19/2012 08:12 PM, Anthony Scopatz wrote:
> Hello Uwe,
>
> Why don't you try something like:
>
> bar = filter(x.description == VideoNode for x in f.walkNodes('/', 'Table'))
>
> or
>
> bar = filter(x.dtype == VideoNode._v_dtype for x in f.walkNodes('/',
> 'Table'))
>
> to compare the dtype / description directly?

correction on my behalf, that would be exactly what I needed, but:

- x.description compares false to a (correct) subclass of 
tables.IsDescription

- a subclass of tables.IsDescription has no property _v_dtype to compare 
to x.dtype (from your example above)


Any other ideas?

Thanks in advance,
Uwe


> On May 18, 2012 8:00 AM, "Uwe Mayer" <uwe...@df...
> <mailto:uwe...@df...>> wrote:
>
>     Hi,
>
>     I have several leaf nodes of the same table dtype:
>
>     class VideoNode(tables.IsDescription):
>         ...
>
>     Not all tables in the hdf5 file are of the same type, however. How
>     do I iterate
>     over all leafes which are tables of the above class, while ignoring
>     tables with
>     different signatures?
>
>     i.e. I'd like to write something like:
>     <code>
>     f = tables.openFile(...)
>     foo = f.walkNodes('/', classname='VideoNode')
>     </code>
>     which does not work because only the class name is "Table"...
>
>     or
>     <code>
>     bar = filter(isinstance(x, VideoNode) for x in f.walkNodes('/',
>     'Table')))
>     </code>
>
>     which does not work, because x is never an instance of VideoNode.
>
>     Any ideas?
>
>     Thanks in advance
>     Uwe
>
>
>     ------------------------------------------------------------------------------
>     Live Security Virtual Conference
>     Exclusive live event will cover all the ways today's security and
>     threat landscape has changed and how IT managers can respond.
>     Discussions
>     will include endpoint security, mobile security and the latest in
>     malware
>     threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
>     _______________________________________________
>     Pytables-users mailing list
>     Pyt...@li...
>     <mailto:Pyt...@li...>
>     https://lists.sourceforge.net/lists/listinfo/pytables-users
>
>
>
> ------------------------------------------------------------------------------
> Live Security Virtual Conference
> Exclusive live event will cover all the ways today's security and
> threat landscape has changed and how IT managers can respond. Discussions
> will include endpoint security, mobile security and the latest in malware
> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
>
>
>
> _______________________________________________
> Pytables-users mailing list
> Pyt...@li...
> https://lists.sourceforge.net/lists/listinfo/pytables-users

Re: [Pytables-users] iterate over specific Tables

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

Hi Uwe,

Sorry, I wrote this when I was away from my computer and so I couldn't test
it.
Our documentation is clearly wrong then.    However, what you *can* do is
take
the dtype from a known VideoNode table and then compare using this.

known_dtype = f.root.path_to_a_video_node.dtype
bar = filter(x.dtype == known_dtype for x in f.walkNodes('/', 'Table'))

Note that in your file your file you could create an empty table with the
VideoNode
description at a specific location just so that you can read out this dtype.

Be Well
Anthony

On Mon, May 21, 2012 at 6:20 AM, Uwe Mayer <uwe...@df...> wrote:

> Hi Anthony,
>
> On 05/19/2012 08:12 PM, Anthony Scopatz wrote:
> > Hello Uwe,
> >
> > Why don't you try something like:
> >
> > bar = filter(x.description == VideoNode for x in f.walkNodes('/',
> 'Table'))
> >
> > or
> >
> > bar = filter(x.dtype == VideoNode._v_dtype for x in f.walkNodes('/',
> > 'Table'))
> >
> > to compare the dtype / description directly?
>
> correction on my behalf, that would be exactly what I needed, but:
>
> - x.description compares false to a (correct) subclass of
> tables.IsDescription
>
> - a subclass of tables.IsDescription has no property _v_dtype to compare
> to x.dtype (from your example above)
>
>
> Any other ideas?
>
> Thanks in advance,
> Uwe
>
>
> > On May 18, 2012 8:00 AM, "Uwe Mayer" <uwe...@df...
> > <mailto:uwe...@df...>> wrote:
> >
> >     Hi,
> >
> >     I have several leaf nodes of the same table dtype:
> >
> >     class VideoNode(tables.IsDescription):
> >         ...
> >
> >     Not all tables in the hdf5 file are of the same type, however. How
> >     do I iterate
> >     over all leafes which are tables of the above class, while ignoring
> >     tables with
> >     different signatures?
> >
> >     i.e. I'd like to write something like:
> >     <code>
> >     f = tables.openFile(...)
> >     foo = f.walkNodes('/', classname='VideoNode')
> >     </code>
> >     which does not work because only the class name is "Table"...
> >
> >     or
> >     <code>
> >     bar = filter(isinstance(x, VideoNode) for x in f.walkNodes('/',
> >     'Table')))
> >     </code>
> >
> >     which does not work, because x is never an instance of VideoNode.
> >
> >     Any ideas?
> >
> >     Thanks in advance
> >     Uwe
> >
> >
> >
> ------------------------------------------------------------------------------
> >     Live Security Virtual Conference
> >     Exclusive live event will cover all the ways today's security and
> >     threat landscape has changed and how IT managers can respond.
> >     Discussions
> >     will include endpoint security, mobile security and the latest in
> >     malware
> >     threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
> >     _______________________________________________
> >     Pytables-users mailing list
> >     Pyt...@li...
> >     <mailto:Pyt...@li...>
> >     https://lists.sourceforge.net/lists/listinfo/pytables-users
> >
> >
> >
> >
> ------------------------------------------------------------------------------
> > Live Security Virtual Conference
> > Exclusive live event will cover all the ways today's security and
> > threat landscape has changed and how IT managers can respond. Discussions
> > will include endpoint security, mobile security and the latest in malware
> > threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
> >
> >
> >
> > _______________________________________________
> > Pytables-users mailing list
> > Pyt...@li...
> > https://lists.sourceforge.net/lists/listinfo/pytables-users
>
>
>
>
> ------------------------------------------------------------------------------
> Live Security Virtual Conference
> Exclusive live event will cover all the ways today's security and
> threat landscape has changed and how IT managers can respond. Discussions
> will include endpoint security, mobile security and the latest in malware
> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
> _______________________________________________
> Pytables-users mailing list
> Pyt...@li...
> https://lists.sourceforge.net/lists/listinfo/pytables-users
>