Re: [Pytables-users] modifying a table column

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

Glad I could help!


On Tue, Aug 27, 2013 at 7:44 PM, Oleksandr Huziy <guz...@gm...>wrote:

> 2013/8/27 Anthony Scopatz <sc...@gm...>
>
>>
>> You are right that this loads the entire computed array into memory and
>> is therefore not optimal.  I would do something like the following:
>>
>> h = tb.open_file(path, mode="a")
>> varTable = h.get_node("/", var_name)
>> coef = 3 * 60 * 60 #output step
>> c = varTable.cols.field
>> expr = tb.Expr("c * m", uservars = {"c": c, "m": coef })
>> expr.set_output(c)
>> expr.eval()
>> varTable.flush()
>> h.close()
>>
>
> Aha, this is cool. Thanks Anthony.
>
> Cheers
> --
> Sasha
>
>
>>
>>>>  On Tue, Aug 27, 2013 at 11:44 AM, Oleksandr Huziy <
>>>> guz...@gm...> wrote:
>>>>
>>>>>  Hi All:
>>>>>
>>>>> I have a huge table imported from other binary files to hdf, and I
>>>>> forgot to multiply the data by a factor in one case. Is there an easy way
>>>>> to multiply a column by a constant factor using pytables?
>>>>> To modify it in place?
>>>>>
>>>>> Thank you
>>>>>
>>>>> --
>>>>> Sasha
>>>>>
>>>>>
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>>
>>
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>
>
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