import scrapy
from scrapy.loader.processors import MapCompose
def filter_spaces(value):
    return value.strip(" ").strip("\n")
class LotItem(scrapy.Item):
    num = scrapy.Field(input_processor=MapCompose(filter_spaces))

 def parse_item(self, response):
    item = LotItem()                    
    item['num'] = response.xpath('//div/span/text()').extract()[0]
    yield item

 "\n1234     "

 numbers = response.xpath('//div/span/text()').re('\d+')
numbers = numbers[0] if numbers else None

 numbers = response.xpath('//div/span/text()').extract_first()
numbers = numbers.strip(" \n") if numbers else None

 .extract()[0]