使用python scrapy爬取天气并导出csv文件

目录

• 爬取xxx天气
• 安装
• 创建scray爬虫项目
• 文件说明
• 开始爬虫
• 补充：scrapy导出csv时字段的一些问题
• 1.字段顺序问题：
• 2.输出csv有空行的问题
• 总结

爬取xxx天气

爬取网址：https://tianqi.2345.com/today-60038.htm

安装

pip install scrapy

我使用的版本是scrapy 2.5

创建scray爬虫项目

在命令行如下输入命令

scrapy startproject name

name为项目名称
如，scrapy startproject spider_weather
之后再输入

scrapy genspider spider_name 域名

如，scrapy genspider changshu tianqi.2345.com

查看文件夹

- spider_weather
   - spider
       - __init__.py
       - changshu.py
   - __init__.py
   - items.py
   - middlewares.py
   - pipelines.py
   - settings.py
- scrapy.cfg

文件说明

名称	作用
scrapy.cfg	项目的配置信息，主要为Scrapy命令行工具提供一个基础的配置信息。（真正爬虫相关的配置信息在settings.py文件中）
items.py	设置数据存储模板，用于结构化数据，如：Django的Model
pipelines	数据处理行为，如：一般结构化的数据持久化
settings.py	配置文件，如：递归的层数、并发数，延迟下载等
spiders	爬虫目录，如：创建文件，编写爬虫规则

开始爬虫

1.在spiders文件夹里面对自己创建的爬虫文件进行数据爬取、如在此案例中的spiders/changshu.py

代码演示如下

import scrapy

class ChangshuSpider(scrapy.Spider):
    name = 'changshu'
    allowed_domains = ['tianqi.2345.com']
    start_urls = ['https://tianqi.2345.com/today-60038.htm']

    def parse(self, response):
        # 日期、天气状态、温度、风级
        # 利用xpath解析数据、不会xpath的同学可以去稍微学习一下，语法简单
        dates = response.xpath('//a[@class="seven-day-item "]/em/text()').getall()
        states = response.xpath('//a[@class="seven-day-item "]/i/text()').getall()
        temps = response.xpath('//a[@class="seven-day-item "]/span[@class="tem-show"]/text()').getall()
        winds = response.xpath('//a[@class="seven-day-item "]/span[@class="wind-name"]/text()').getall()
        # 返回每条数据
        for date, state, temp, wind in zip(dates,states,temps,winds):
            yield {
                'date' : date,
                'state': state,
                'temp': temp,
                'wind': wind
            }

2.在settings.py文件中进行配置

修改UA

USER_AGENT = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/95.0.4638.69 Safari/537.36' 

修改机器爬虫配置

ROBOTSTXT_OBEY = False 

整个文件如下：

# Scrapy settings for spider_weather project
#
# For simplicity, this file contains only settings considered important or
# commonly used. You can find more settings consulting the documentation:
#
#     https://docs.scrapy.org/en/latest/topics/settings.html
#     https://docs.scrapy.org/en/latest/topics/downloader-middleware.html
#     https://docs.scrapy.org/en/latest/topics/spider-middleware.html

BOT_NAME = 'spider_weather'

SPIDER_MODULES = ['spider_weather.spiders']
NEWSPIDER_MODULE = 'spider_weather.spiders'


# Crawl responsibly by identifying yourself (and your website) on the user-agent
USER_AGENT = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/95.0.4638.69 Safari/537.36'

# Obey robots.txt rules
ROBOTSTXT_OBEY = False

# Configure maximum concurrent requests performed by Scrapy (default: 16)
#CONCURRENT_REQUESTS = 32

# Configure a delay for requests for the same website (default: 0)
# See https://docs.scrapy.org/en/latest/topics/settings.html#download-delay
# See also autothrottle settings and docs
#DOWNLOAD_DELAY = 3
# The download delay setting will honor only one of:
#CONCURRENT_REQUESTS_PER_DOMAIN = 16
#CONCURRENT_REQUESTS_PER_IP = 16

# Disable cookies (enabled by default)
#COOKIES_ENABLED = False

# Disable Telnet Console (enabled by default)
#TELNETCONSOLE_ENABLED = False

# Override the default request headers:
#DEFAULT_REQUEST_HEADERS = {
#   'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
#   'Accept-Language': 'en',
#}

# Enable or disable spider middlewares
# See https://docs.scrapy.org/en/latest/topics/spider-middleware.html
#SPIDER_MIDDLEWARES = {
#    'spider_weather.middlewares.SpiderWeatherSpiderMiddleware': 543,
#}

# Enable or disable downloader middlewares
# See https://docs.scrapy.org/en/latest/topics/downloader-middleware.html
#DOWNLOADER_MIDDLEWARES = {
#    'spider_weather.middlewares.SpiderWeatherDownloaderMiddleware': 543,
#}

# Enable or disable extensions
# See https://docs.scrapy.org/en/latest/topics/extensions.html
#EXTENSIONS = {
#    'scrapy.extensions.telnet.TelnetConsole': None,
#}

# Configure item pipelines
# See https://docs.scrapy.org/en/latest/topics/item-pipeline.html
# ITEM_PIPELINES = {
#    'spider_weather.pipelines.SpiderWeatherPipeline': 300,
# }

# Enable and configure the AutoThrottle extension (disabled by default)
# See https://docs.scrapy.org/en/latest/topics/autothrottle.html
#AUTOTHROTTLE_ENABLED = True
# The initial download delay
#AUTOTHROTTLE_START_DELAY = 5
# The maximum download delay to be set in case of high latencies
#AUTOTHROTTLE_MAX_DELAY = 60
# The average number of requests Scrapy should be sending in parallel to
# each remote server
#AUTOTHROTTLE_TARGET_CONCURRENCY = 1.0
# Enable showing throttling stats for every response received:
#AUTOTHROTTLE_DEBUG = False

# Enable and configure HTTP caching (disabled by default)
# See https://docs.scrapy.org/en/latest/topics/downloader-middleware.html#httpcache-middleware-settings
#HTTPCACHE_ENABLED = True
#HTTPCACHE_EXPIRATION_SECS = 0
#HTTPCACHE_DIR = 'httpcache'
#HTTPCACHE_IGNORE_HTTP_CODES = []
#HTTPCACHE_STORAGE = 'scrapy.extensions.httpcache.FilesystemCacheStorage'

3.然后在命令行中输入如下代码

scrapy crawl changshu -o weather.csv 

4.结果如下

补充：scrapy导出csv时字段的一些问题

scrapy -o csv格式输出的时候，发现输出文件中字段的顺序不是按照items.py中的顺序，也不是爬虫文件中写入的顺序，这样导出的数据因为某些字段变得不好看，此外，导出得csv文件不同的item之间被空行隔开，本文主要描述解决这些问题的方法。

1.字段顺序问题：

需要在scrapy的spiders同层目录，新建csv_item_exporter.py文件内容如下（文件名可改，目录定死）

from scrapy.conf import settings from scrapy.contrib.exporter import CsvItemExporter class MyProjectCsvItemExporter(CsvItemExporter): def init(self, *args, kwargs): delimiter = settings.get(‘CSV_DELIMITER', ‘,') kwargs[‘delimiter'] = delimiter fields_to_export = settings.get(‘FIELDS_TO_EXPORT', []) if fields_to_export : kwargs[‘fields_to_export'] = fields_to_export super(MyProjectCsvItemExporter, self).init(*args, kwargs)

2)在settings.py中新增以下内容

#定义输出格式 FEED_EXPORTERS = { ‘csv': ‘project_name.spiders.csv_item_exporter.MyProjectCsvItemExporter', } #指定csv输出字段的顺序 FIELDS_TO_EXPORT = [ ‘name', ‘title', ‘info' ] #指定分隔符 CSV_DELIMITER = ‘,'

设定完毕，执行scrapy crawl spider -o spider.csv的时候，字段就按顺序来了

2.输出csv有空行的问题

此时你可能会发现csv文件中有空行，这是因为scrapy默认输出时，每个item之间的分隔符是空行

解决办法：

在找到exporters.py的CsvItemExporter类，大概在215行中增加newline="",即可。

也可以继承重写CsvItemExporter类

总结

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