James Stroud wrote:
> Wensui Liu wrote:
>
>> Dear all,
>>
>> is there a way to create a 2-dimension-table-like object such that I
>> can reference a whole column directly using something like :
>> mytable.column1 ?
>>
>> by the way, can python be used for database programming to pull large
>> volume data (hundred M or even several Gs) out of large database and
>> do data manipulation and reporting ? if yes, how is the speed and
>> efficiency ?
>>
>> thanks.
>>
>> wensui
>
>
> I have a table class that works like this:
>
> atable['some_col'] ==> list of values
> atable[some_row_index] ==> list of values
> atable[slice_start:slice_end] ==> new table
> atable[('some_col', 'other_col', 'another_col')] ==> 3 col. table
> atable['some_col', some_row_index] ==> one value
> atable['some_col', slice_start:slice_end] ==> list of values
> atable[('some_col', 'other_col'), some_row_index] ==> list of 2 vals
> atable[('some_col', 'other_col'), slice_start:end]) ==> 2 col. table
>
> As you can see, it has a lot of flexibility, but may not be the ultimate
> in terms of speed (and purists may not like the way __getitem__ returns
> data based on context). It is for people who care about convenience over
> speed and do not adhere to some puritanical ideal about how __getitem__
> should work. There is little typechecking (in accord with my own brand
> of puritanical philosophy), so be careful if you have ints as column
> headers. The datastructure is implemented as a list of lists (by row)
> and the "keys" (column headings) are a list. So size limitations are
> limited by memory. Theoretically, the __getitem__ (where all the work
> and decisions are done) could be factored out and wrapped around dbi for
> hard-core database usage. This might entail some serious creativity.
>
> It also has some other features, such as returning matches, etc. It is
> not intended, at all, to rival an actual database such as mysql--the
> model is more based on how Joe Users use excel files.
>
> If you are interested, I can send you the module. Beyond actual use in
> my own and my wife's work, there has been little testing.
>
> James
Also, if you want columns as attributes (which may be pretty cool):
def __getattr__(self, att):
if att in self.headers:
return self[att]
else:
return self.__getattribute__(att)
James
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