If using a dictionary but still requiring attribute access, techniques such
as those used at https://github.com/holdenweb/hw can be used to simply
client code.
Kind regards,
Steve Holden
On Wed, Oct 30, 2019 at 11:15 AM Oz Tiram <oz.ti...@gmail.com> wrote:
> Hi Steve,
>
> Thanks for your reply. While dataclass provide a cleaner API than DictRow
> (you can access `row.id` instead of `row["id"]`).
> However, dataclass still use the built in `__dict__` instead of
> `__slots__`.
>
> ```
> >>> @dataclass
> ... class InventoryItem:
> ... '''Class for keeping track of an item in inventory.'''
> ... name: str
> ... unit_price: float
> ... quantity_on_hand: int = 0
> ...
>
> >>> cf = InventoryItem("cornflakes", 0.99, 123)
> >>> cf
> InventoryItem(name='cornflakes', unit_price=0.99, quantity_on_hand=123)
> >>> cf.__dict__
> {'name': 'cornflakes', 'unit_price': 0.99, 'quantity_on_hand': 123}
> ```
>
> This means that the users reading large files won't see the suggested
> memory improvements.
>
> On the other hand, I'm willing to implement CSVReader classes for both.
> `DataClassCSVReader` does offer the
> benefit of row instances being mutable, `NamedTupleCSVReader` can be
> useful for people leaning toward functional
> programming style, where queries on CSV are only meant to find items or
> calculate quantities quickly without actually
> modifying the rows.
>
> I would be more than happy to know whether such PR would accept.
>
> Best regards
> Oz
>
>
> On Wed, Oct 30, 2019 at 8:39 AM Steve Holden <st...@holdenweb.com> wrote:
>
>> Since 3.7 it may be that dataclasses offer a cleaner implementation of
>> the functionality you suggest. It shouldn't be too difficult to produce
>> code that uses dataclasses in 3.7+ but falls back to namedtuples when
>> necessary. You may wish to consider such an implementation strategy.
>>
>> Best wishes,
>> Steve Holden
>>
>>
>> On Tue, Oct 29, 2019 at 10:59 PM Oz Tiram <oz.ti...@gmail.com> wrote:
>>
>>> Hello Python-devs,
>>>
>>> The csv module is probably heavily utilized by newcomers to Python,
>>> being a very popular data exchange format.
>>> Although, there are better tools for processing tabular data like
>>> SQLite, or Pandas, I suspect this is still a very popular
>>> module.
>>> There are many examples floating around how one can read and process CSV
>>> with the csv module.
>>> Quite a few tutorials show how to use namedtuple to gain memory saving
>>> and speed, over the DictReader.
>>> Python's own documentation has got a recipe in the collections modules[1]
>>> Hence, I was wondering why not go the extra step and add a new class to
>>> the CSV module NamedTupleReader?
>>> This class would do a good service for Python's users, especially
>>> newcomers who are still not aware of
>>> modules like the collections module.
>>> Would someone be willing to sponsor and review such a PR from me?
>>> As a smaller change, we could simply add a link from the CSV module's
>>> documentation to the recipe in the collections module.
>>> What do you think?
>>>
>>> Best regards
>>> Oz
>>>
>>> [1]:
>>> https://docs.python.org/3/library/collections.html?highlight=namedtuple%20csv#collections.namedtuple
>>>
>>> ---
>>> Imagine there's no countries
>>> it isn't hard to do
>>> Nothing to kill or die for
>>> And no religion too
>>> Imagine all the people
>>> Living life in peace
>>>
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>>
>
> --
>
>
> ---
>
> Imagine there's no countries
> it isn't hard to do
> Nothing to kill or die for
> And no religion too
> Imagine all the people
> Living life in peace
>
>
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