Question

我在生成的csv输出文件中的每行scrapy输出之间得到了不需要的空行。

我已经从python2迁移到python 3，并且我使用的是Windows 10.因此我正在调整我的scthon项目python3。

我当前（现在，唯一的）问题是当我将scrapy输出写入CSV文件时，我在每行之间得到一个空行。这里有几个帖子突出显示（这与Windows有关），但我无法找到解决方案。

实际上，我还在piplines.py文件中添加了一些代码，以确保csv输出处于给定的列顺序而不是一些随机顺序。因此，我可以使用普通scrapy crawl charleschurch来运行此代码而不是scrapy crawl charleschurch -o charleschurch2017xxxx.csv

有人知道如何在CSV输出中跳过/省略此空白行吗？

我的pipelines.py代码在下面（我可能不需要import csv行，但我怀疑我可以做最后的答案）：

# -*- coding: utf-8 -*-

# Define your item pipelines here
#
# Don't forget to add your pipeline to the ITEM_PIPELINES setting
# See: http://doc.scrapy.org/en/latest/topics/item-pipeline.html

import csv
from scrapy import signals
from scrapy.exporters import CsvItemExporter

class CSVPipeline(object):

  def __init__(self):
    self.files = {}

  @classmethod
  def from_crawler(cls, crawler):
    pipeline = cls()
    crawler.signals.connect(pipeline.spider_opened, signals.spider_opened)
    crawler.signals.connect(pipeline.spider_closed, signals.spider_closed)
    return pipeline

  def spider_opened(self, spider):
    file = open('%s_items.csv' % spider.name, 'w+b')
    self.files[spider] = file
    self.exporter = CsvItemExporter(file)
    self.exporter.fields_to_export = ["plotid","plotprice","plotname","name","address"]
    self.exporter.start_exporting()

  def spider_closed(self, spider):
    self.exporter.finish_exporting()
    file = self.files.pop(spider)
    file.close()

  def process_item(self, item, spider):
    self.exporter.export_item(item)
    return item

我将此行添加到settings.py文件中（不确定300的相关性）：

ITEM_PIPELINES = {'CharlesChurch.pipelines.CSVPipeline': 300 }

我的scrapy代码如下：

import scrapy
from urllib.parse import urljoin

from CharlesChurch.items import CharleschurchItem

class charleschurchSpider(scrapy.Spider):
    name = "charleschurch"
    allowed_domains = ["charleschurch.com"]    
    start_urls = ["https://www.charleschurch.com/county-durham_willington/the-ridings-1111"]


    def parse(self, response):

        for sel in response.xpath('//*[@id="aspnetForm"]/div[4]'):
           item = CharleschurchItem()
           item['name'] = sel.xpath('//*[@id="XplodePage_ctl12_dsDetailsSnippet_pDetailsContainer"]/span[1]/b/text()').extract()
           item['address'] = sel.xpath('//*[@id="XplodePage_ctl12_dsDetailsSnippet_pDetailsContainer"]/div/*[@itemprop="postalCode"]/text()').extract()
           plotnames = sel.xpath('//div[@class="housetype js-filter-housetype"]/div[@class="housetype__col-2"]/div[@class="housetype__plots"]/div[not(contains(@data-status,"Sold"))]/div[@class="plot__name"]/a/text()').extract()
           plotnames = [plotname.strip() for plotname in plotnames]
           plotids = sel.xpath('//div[@class="housetype js-filter-housetype"]/div[@class="housetype__col-2"]/div[@class="housetype__plots"]/div[not(contains(@data-status,"Sold"))]/div[@class="plot__name"]/a/@href').extract()
           plotids = [plotid.strip() for plotid in plotids]
           plotprices = sel.xpath('//div[@class="housetype js-filter-housetype"]/div[@class="housetype__col-2"]/div[@class="housetype__plots"]/div[not(contains(@data-status,"Sold"))]/div[@class="plot__price"]/text()').extract()
           plotprices = [plotprice.strip() for plotprice in plotprices]
           result = zip(plotnames, plotids, plotprices)
           for plotname, plotid, plotprice in result:
               item['plotname'] = plotname
               item['plotid'] = plotid
               item['plotprice'] = plotprice
               yield item

Answer 1

我怀疑不理想，但我找到了解决这个问题的方法。在pipelines.py文件中，我添加了更多基本上用空行读取csv文件到代码列表的代码，因此删除空白行，然后将清理后的列表写入新文件。

我添加的代码是：

with open('%s_items.csv' % spider.name, 'r') as f:
  reader = csv.reader(f)
  original_list = list(reader)
  cleaned_list = list(filter(None,original_list))

with open('%s_items_cleaned.csv' % spider.name, 'w', newline='') as output_file:
    wr = csv.writer(output_file, dialect='excel')
    for data in cleaned_list:
      wr.writerow(data)

所以整个pipelines.py文件是：

# -*- coding: utf-8 -*-

# Define your item pipelines here
#
# Don't forget to add your pipeline to the ITEM_PIPELINES setting
# See: http://doc.scrapy.org/en/latest/topics/item-pipeline.html

import csv
from scrapy import signals
from scrapy.exporters import CsvItemExporter

class CSVPipeline(object):

  def __init__(self):
    self.files = {}

  @classmethod
  def from_crawler(cls, crawler):
    pipeline = cls()
    crawler.signals.connect(pipeline.spider_opened, signals.spider_opened)
    crawler.signals.connect(pipeline.spider_closed, signals.spider_closed)
    return pipeline

  def spider_opened(self, spider):
    file = open('%s_items.csv' % spider.name, 'w+b')
    self.files[spider] = file
    self.exporter = CsvItemExporter(file)
    self.exporter.fields_to_export = ["plotid","plotprice","plotname","name","address"]
    self.exporter.start_exporting()

  def spider_closed(self, spider):
    self.exporter.finish_exporting()
    file = self.files.pop(spider)
    file.close()

    #given I am using Windows i need to elimate the blank lines in the csv file
    print("Starting csv blank line cleaning")
    with open('%s_items.csv' % spider.name, 'r') as f:
      reader = csv.reader(f)
      original_list = list(reader)
      cleaned_list = list(filter(None,original_list))

    with open('%s_items_cleaned.csv' % spider.name, 'w', newline='') as output_file:
        wr = csv.writer(output_file, dialect='excel')
        for data in cleaned_list:
          wr.writerow(data)

  def process_item(self, item, spider):
    self.exporter.export_item(item)
    return item


class CharleschurchPipeline(object):
    def process_item(self, item, spider):
        return item

不理想，但现在解决了这个问题。

Answer 2

b中的w+b很可能是问题的一部分，因为这会使文件被视为二进制文件，因此换行符按原样编写。

所以第一步是删除b。然后通过添加U，您还可以激活通用换行支持（请参阅：https://docs.python.org/3/glossary.html#term-universal-newlines）

所以有问题的行应该是这样的：

file = open('%s_items.csv' % spider.name, 'Uw+')

Scrapy python csv输出在每行之间有空行

2 个答案: