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 <[email protected]> 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 <[email protected]> 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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