Re: [Pytables-users] Support for Arrays in Tables

[Edward H. <ha...@co...>]

On Sunday, April 13, 2003, at 06:37  am, Francesc Alted wrote:

> A Dissabte 12 Abril 2003 17:43, Edward Hartley va escriure:
>>
Many thanks for the speedy reply
>> is there going to be  support for arrays in tabels
>> specifically what I'm trying to do is put arrays into
>> tables as leafs. I may be mistaken but I think this is
>> currently not supported but the creation of arrays from
>> table data is.
>
> I don't understand well your question. The Array and Table objects are 
> Leaf
> objects, so you can't have an Array with a Table as parent.
>
Sorry about my inaccuracy about the terminology
> However, Table do accept numarray arrays as columns elements in this 
> way:
>
> field = Col("Float32", 3)
>
yes I was aware of that
> where 3 means the number of elements of your array. 0.4 version only
> supports unidimensional arrays as elements, however. This is an actual
> limitation on numarray code, that will be removed soon (I hope).
>
Ah I hadn't realised
> Another possibility may be to use attributes to attach an array to a 
> Table
> object through the use of the setAttr() method available on Leaf 
> objects.
> Right now, only character attributes are supported, but by combining 
> them
> with cPikle, you can attach any object you may want to a Leaf.
>
This is interesting
I have found another way to get around the issue by specifying the 
shape in one field
class my_array(IsDescription):
	array_ shape = Col('UInt8', shape)
	ravelled_array=Col('UInt8' , data)
it occurs to me that with suitable accessor methods this would solve it 
completely?
many thanks once again
Ed Hartley


>
> -- 
> Francesc Alted
>
>
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