从python / scrapy（python framework）在单个csv文件中将数据写入多个

我正在使用scrapy框架，并通过创建两个蜘蛛文件从两个url获取数据。

现在，例如，当我运行时spider1，url1所抓取的数据将保存到csv1文件中，而当我运行第二次时spider2，数据将保存到csv2文件中。

实际上我想做的是将来自不同Spider的所有数据保存到不同工作表中的单个CSV文件中（工作表名称应为Spider名称）

All about my question is how to write data in to multiple sheets in a single csv file from python
pipe.py

from w3c_browser.items import WCBrowserItem
import csv
from csv import DictWriter
from cStringIO import StringIO
from datetime import datetime
from scrapy.xlib.pydispatch import dispatcher
from scrapy import signals
from scrapy import log

class W3CBrowserPipeline(object):
    def __init__(self):
        dispatcher.connect(self.spider_opened, signal=signals.spider_opened)
        dispatcher.connect(self.spider_closed, signal=signals.spider_closed)
        self.brandCategoryCsv = csv.writer(open('wcbbrowser.csv', 'wb'))

    def spider_opened(self, spider):
        spider.started_on = datetime.now()
        if spider.name == 'browser_statistics':
            log.msg("opened spider  %s at time %s" % (spider.name,datetime.now().strftime('%H-%M-%S')))
            self.brandCategoryCsv = csv.writer(open("csv/%s-%s.csv"% (spider.name,datetime.now().strftime('%d%m%y')), "wb"),
                       delimiter=',', quoting=csv.QUOTE_MINIMAL)
        elif spider.name == 'browser_os':
            log.msg("opened spider  %s at time %s" % (spider.name,datetime.now().strftime('%H-%M-%S')))
            self.brandCategoryCsv = csv.writer(open("csv/%s-%s.csv"% (spider.name,datetime.now().strftime('%d%m%y')), "wb"),
                       delimiter=',', quoting=csv.QUOTE_MINIMAL)
        elif spider.name == 'browser_display':
            log.msg("opened spider  %s at time %s" % (spider.name,datetime.now().strftime('%H-%M-%S')))
            self.brandCategoryCsv = csv.writer(open("csv/%s-%s.csv"% (spider.name,datetime.now().strftime('%d%m%y')), "wb"),
                       delimiter=',', quoting=csv.QUOTE_MINIMAL)

    def process_item(self, item, spider):
        if spider.name == 'browser_statistics':
            self.brandCategoryCsv.writerow([item['year'],
                                            item['internet_explorer'],
                                            item['firefox'],
                                            item['chrome'],
                                            item['safari'],
                                            item['opera'],
            ])
            return item

        elif spider.name == 'browser_os':
            def process_item(self, item, spider):
                self.brandCategoryCsv.writerow([item['year'],
                                                item['vista'],
                                                item['nt'],
                                                item['winxp'],
                                                item['linux'],
                                                item['mac'],
                                                item['mobile'],
                ])
                return item

    def spider_closed(self, spider):
        log.msg("closed spider %s at %s" % (spider.name,datetime.now().strftime('%H-%M-%S')))
        work_time = datetime.now() - spider.started_on
        print str(work_time),"Total Time taken by the spider to run>>>>>>>>>>>"