title: scrapy empty csv file
body: <p>I'm trying to run my scrapy spider, it returns no error but output his an empty csv file </p>
  
  <p>i'm launching the spider through command line scrapy crawl AnimeReviews -o AnimeReviews.csv -t csv</p>
  
  <p>this is library that i used</p>
  
  <pre><code>import scrapy
  import json
  from functools import reduce
  from scrapy.selector import Selector
  from AnimeReviews.items import AnimereviewsItem
  last_page = 1789
  </code></pre>
  
  <p>this is my spider</p>
  
  <pre><code>class AnimeReviewsSpider(scrapy.Spider):
      name = 'AnimeReviews_spider'
      allowed_urls =['myanimelist.net']
      start_urls = ['https://myanimelist.net/reviews.php?t=anime']
  
  def parse(self, response):
      page_urls = [response.url + "&amp;p=" + str(pageNumber) for pageNumber in range(1, last_page+1)]
      for page_url in page_urls:
          yield scrapy.Request(page_url,
              callback = self.parse_reviews_page)
  
  def parse_reviews_page(self, response):
      item = AnimereviewsItem()
      reviews = response.xpath('//*[@class="borderDark pt4 pb8 pl4 pr4 mb8"]').extract()       #each page displays 50 reviews
  
      for review in reviews:
          anime_title = Selector(text = review).xpath('//div[1]/a[1]/strong/text()').extract()
          anime_url = Selector(text = review).xpath('//a[@class="hoverinfo_trigger"]/@href').extract()
          anime_url = map(lambda x: 'https://myanimelist.net'+ x ,anime_url)
          review_time = Selector(text = review).xpath('//*[@style="float: right;"]/text()').extract()[0]
          reviewer_name = Selector(text = review).xpath('//div[2]/table/tr/td[2]/a/text()').extract()
          rating = Selector(text = review).xpath('//div[2]/table/tr/td[3]/div[2]/text()').extract()
          for i in range(len(rating)):
              rating_temp = rating[i]
              rating[i] = rating_temp.split(" ")[1]
          review_text = Selector(text = review).xpath('//*[@class="spaceit textReadability word-break"]').extract()
          for i in range(len(review_text)):
              text = Selector(text = review_text[i]).xpath('//text()').extract()
          pic_url = Selector(text = review).xpath('//div[3]/div[1]/div[1]/a/img/@data-src').extract()
          item['anime_title'] = anime_title
          item['anime_url'] = anime_url
          item['review_time'] = review_time
          item['reviewer'] = reviewer_name
          item['rating'] = rating
          item['review_text'] = review_text
          item['pic_url'] = pic_url
          yield item
  </code></pre>
  
  <p>this is log after crawling </p>
  
  <pre><code>2018-06-22 13:37:14 [scrapy.core.engine] INFO: Closing spider (finished)
  2018-06-22 13:37:14 [scrapy.statscollectors] INFO: Dumping Scrapy stats:
  {'downloader/request_bytes': 698849,
   'downloader/request_count': 1791,
   'downloader/request_method_count/GET': 1791,
   'downloader/response_bytes': 148209070,
   'downloader/response_count': 1791,
   'downloader/response_status_count/200': 1791,
   'finish_reason': 'finished',
   'finish_time': datetime.datetime(2018, 6, 22, 11, 37, 14, 546133),
   'log_count/DEBUG': 1792,
   'log_count/INFO': 13,
   'request_depth_max': 1,
   'response_received_count': 1791,
   'scheduler/dequeued': 1790,
   'scheduler/dequeued/memory': 1790,
   'scheduler/enqueued': 1790,
   'scheduler/enqueued/memory': 1790,
   'start_time': datetime.datetime(2018, 6, 22, 11, 30, 38, 403920)}
  2018-06-22 13:37:14 [scrapy.core.engine] INFO: Spider closed (finished)
  </code></pre>
  
  <p>if you need more informations let me know. </p>