Item pipelines 无法为每个输入项生成多个项。 Create a spider middleware 而是使用它 ​process_spider_output()​ 方法。例如：

from copy import deepcopy

from itemadapter import is_item, ItemAdapter

class MultiplyItemsMiddleware:

    def process_spider_output(self, response, result, spider):
        for item in result:
            if is_item(item):
                adapter = ItemAdapter(item)
                for _ in range(adapter['multiply_by']):
                    yield deepcopy(item)