Hello Edward,
What is going on is that in Python (and elsewhere) there is a distinction
between changing the elements of a container (appending, inserting, and
deleting) and changing the container itself (ie swapping one list out for
another list object). Currently PyTables attrs only catch changes on the
latter. (Obviously scalars don't have this problem.)
With some clever hacks or a flush method on attrs this could probably be
fixed on the PyTables side. (Please open an issue on GitHub if you would
like to see this implemented.)
However, the quick work around for you right now is to (after you have made
all of the changes you wish to) reset the attr to itself, a la:
mytable.attrs.mylist = mytable.attrs.mylist
Be Well
Anthony
On Fri, Nov 4, 2011 at 1:31 AM, PyTables Org <pytab...@googlemail.com>wrote:
> Forwarding to the list. ~Josh
>
> Begin forwarded message:
>
> *From: *pytables-users-boun...@lists.sourceforge.net
> *Date: *November 4, 2011 1:16:34 AM GMT+01:00
> *To: *pytables-users-ow...@lists.sourceforge.net
> *Subject: **Auto-discard notification*
>
> The attached message has been automatically discarded.
> *From: *"Edward C. Jones" <edcjo...@comcast.net>
> *Date: *November 4, 2011 1:14:17 AM GMT+01:00
> *To: *pytables-users@lists.sourceforge.net
> *Subject: **Changes in container attributes not preserved in the h5 file*
>
>
> My computer has an up-to-date Debian stable distribution installed. It
> comes with Python 2.6.6.
> I have compiled and installed PyTables 2.3.
>
> Here are two small programs:
>
> Program 1:
>
> #! /usr/bin/env python
>
> import tables
>
> h5file = tables.openFile("table1.h5", mode = "w")
>
> class silly_class(tables.IsDescription):
> char = tables.StringCol(1, pos=1)
>
> mytable = h5file.createTable(h5file.root, 'silly', silly_class, "silly")
> mytable.attrs.myint = 5
> mytable.attrs.mylist = [0, 1]
> mytable.attrs.mydict = {1 : 'a', 2 : 'b'}
> mytable.attrs.myint += 2
> mytable.attrs.mylist.append(2)
> mytable.attrs.mydict[3] = 'c'
> print mytable.attrs.myint, mytable.attrs.mylist, mytable.attrs.mydict
> h5file.close()
>
> Program 2:
>
> #! /usr/bin/env python
>
> import tables
>
> h5file = tables.openFile("table1.h5", mode = "r+")
> print h5file.root.silly.attrs.myint, h5file.root.silly.attrs.mylist, \
> h5file.root.silly.attrs.mydict
> h5file.close()
>
> I run program 1 and the printout is: "7 [0, 1, 2] {1: 'a', 2: 'b', 3:
> 'c'}".
> Then I run program 2 where the printout is: "7 [0, 1] {1: 'a', 2: 'b'}".
>
> When an attribute is a Python container, and I make changes inside the
> container, these changes
> are not present when "table1.h5" is reopened. What am I doing wrong?
>
>
>
>
>
>
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