我想写到csv文件中

 for rss in rsslinks:
  item = AppleItem()
  item['reference_link'] = response.url
  base_url = get_base_url(response)
  item['rss_link'] = urljoin_rfc(base_url,rss)
  #item['rss_link'] = rss
  items.append(item)
  #items.append("\n")
 f = open(filename,'a+')    #filename is apple.com.csv
 for item in items:
    f.write("%s\n" % item)

我的输出是这样的：

{'reference_link': 'http://www.apple.com/'
 'rss_link': 'http://www.apple.com/rss '
{'reference_link': 'http://www.apple.com/rss/'
 'rss_link':   'http://ax.itunes.apple.com/WebObjects/MZStore.woa/wpa/MRSS/newreleases/limit=10/rss.xml'}
{'reference_link': 'http://www.apple.com/rss/'
 'rss_link':  'http://ax.itunes.apple.com/WebObjects/MZStore.woa/wpa/MRSS/newreleases/limit=25/rss.xml'}

我想要的是这种格式：

reference_link               rss_link  
http://www.apple.com/     http://www.apple.com/rss/