Re: [Pytables-users] modifying a table column

[Oleksandr H. <guz...@gm...>]

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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