On Mon, Jul 12, 2010 at 9:09 PM, Tim Evans <[email protected]> wrote:
> On 2010-07-13 3:48, Cornelius Kölbel wrote:
>> Dear list,
>>
>> I got an array of dictionaries, that I want to add to a GTKListStore,
>> that is displayed an a treeview.
>>
>> This is very slow. I already replaced the liststore.append by
>> liststore.insert, which is much much faster.
>> But still, filling the 10.000 values takes about 50 seconds.
>>
>> Is there any cool mapping function, to push the array to the liststore?
>> I used a for loop to iterate over the array...
>> I also tried while an to pop the array elements...
>>
>> It is something like this:
>>
>> data: array of dictionaries
>>
>> data = array( { 'v1' : 'something', 'v2': 'something else' } ,
>> { 'v1' : 'another', 'v2': 'something completely diff' }
>> )
>>
>>
>> for d in data:
>> self.liststore.insert( 0, ( d.get("v1"), d.get("v2") ....))
>>
>>
>> ...is there a better way than doing a for loop?
>> ...or a way to not have to interate over the 10.000 dicts?
>>
>> ...or is there a cool reading on performance tuning pyton?
>
> Some general ideas:
> - Make sure the store isn't being viewed when you insert data, that
> will slow it down.
>
> - Do attribute lookups outside big loops:
>
> append = self.liststore.append
> get = d.get
> for d in data:
> append(0, (get('v1'), get('v2'), ...))
This sample won't work since you are using "d" before it is bound in
the for loop. Also, the "append" method only takes one argument: the
row to be added to the store. Here's another way, assuming that there
are not too many keys to be looked up:
append = self.liststore.append
from operator import itemgetter
v1 = itemgetter('v1')
v2 = itemgetter('v2')
v3 = itemgetter('v3')
...
for d in data:
append((v1(d), v2(d), v3(d), ...))
Yet another approach: If you can use OrderedDict (new in Python 2.7
and 3.1), you can do this:
append = self.liststore.append
for d in data:
append(d.values())
>
> - Put the treeview into fixed height and width mode. Automatic sizing
> is the enemy of treeview performance. This only works if all your
> rows are the same height. The function calls you need are:
> gtk.TreeViewColumn.set_sizing
> with the gtk.TREE_VIEW_COLUMN_FIXED value
> gtk.TreeViewColumn.set_fixed_width
> gtk.TreeView.set_fixed_height_mode
>
> - If your list is large enough it may be worth subclassing
> gtk.TreeModel and overriding the required methods. It's complex, but
> it can avoid referencing all your data at tree build time, instead
> loading as the user scrolls.
>
> - Write it in C. Always valid, even if as a last resort.
>
> --
> Tim Evans
> Applied Research Associates NZ
> http://www.aranz.com/
> _______________________________________________
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> Read the PyGTK FAQ: http://faq.pygtk.org/
>
--
Gerald Britton
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