Save data in item wihitn Scrapy and Python

Question

I need to store data in Scrapy Item in parts. To update only the information that I found at the moment.

I did it, but the code looks too verbose. Three lines I repeat very often:

price['pricereg'] = pricereg
price['priceprolong'] = priceprolong 
price['pricechange'] = pricechange 

Is it possible to make the code shorter?

EMPTY_PRICE = {
 'pricereg': None,
 'priceprolong': None,
 'pricechange': None,
 }
item['name'] = "some name"
 price = item.get('price', EMPTY_PRICE)
 price['pricereg'] = pricereg
 price['priceprolong'] = priceprolong
 item['price'] = price
item['name'] = "some name" 
 price = item.get('price', EMPTY_PRICE)
 price['pricechange'] = pricechange 
 item['price'] = price

Answer 1

Have you tried using a collections.namedtuple or a dataclasses.dataclass rather than a dict?

from collections import namedtuple
Item = namedtuple('Item', ['name', 'pricereg', 'priceprolong', 'price'],
 defaults=['', None, None, None])
EMPTY_ITEM = Item()
item['name'] = Item('name', pricereg, priceprolong, price)
print(item['name']._asdict())

or

from dataclasses import dataclass
@dataclass
class Item:
 name: str
 pricereg: int|None = None
 priceprolong: int|None = None
 price: int|None = None
EMPTY_ITEM = Item()
item['name'] = Item('name', pricereg, priceprolong, price)
print(item['name'].pricereg)

alternatively, if you're just setting the dict in one go:

item['name'] = {'pricereg': pricereg, 
 'priceprolong': priceprolong,
 'pricechange': pricechange if pricechange else None, # For defaults 
 'price': price}

If it's to do with setting it up in parts, you can build the dict with the parts you have and do a dict.update

item['name'] = {'pricereg': pricereg, 
 'priceprolong': priceprolong}
tmp = {
 'pricechange': pricechange if pricechange else None, # For defaults 
 'price': price}
item['name'].update(tmp)

• MariaCurie: Thanks, i will try both solutions because i just learn Python