页面上的Python抓取仍包含类似于\r \n \t的字符

Question

我正在尝试使用scrapy 0.20.2在http://www.dmoz.org/Computers/Programming/Languages/Python/Books上刮这个页面。

我可以做我需要的所有事情，比如获取信息和分类...

但是，我仍然在结果中得到\r和\t和\n。例如，这是一个json {"desc": ["\r\n\t\t\t\r\n ", " \r\n\t\t\t\r\n - The primary goal of this book is to promote object-oriented design using Python and to illustrate the use of the emerging object-oriented design patterns.\r\nA secondary goal of the book is to present mathematical tools just in time. Analysis techniques and proofs are presented as needed and in the proper context.\r\n \r\n "], "link": ["http://www.brpreiss.com/books/opus7/html/book.html"], "title": ["Data Structures and Algorithms with Object-Oriented Design Patterns in Python"]},。

数据是正确的，但我不想在结果中看到\t、\r和\n。

我的蜘蛛是

from scrapy.spider import BaseSpider
from scrapy.selector import Selector

from dirbot.items import DmozItem

class DmozSpider(BaseSpider):
   name = "dmoz"
   allowed_domains = ["dmoz.org"]
   start_urls = [
       "http://www.dmoz.org/Computers/Programming/Languages/Python/Books/"
   ]

   def parse(self, response):
       sel = Selector(response)
       sites = sel.xpath('//ul[@class="directory-url"]/li')
       items = []
       for site in sites:
           item = DmozItem()
           item['title'] = site.xpath('a/text()').extract()
           item['link'] = site.xpath('a/@href').extract()
           item['desc'] = site.xpath('text()').extract()
           items.append(item)
       return items

Answer 1

我使用：

def parse(self, response):
    sel = Selector(response)
    sites = sel.xpath('//ul/li')
    items = []
    for site in sites:
        item = DmozItem()
        item['title'] = map(unicode.strip,site.xpath('a/text()').extract())
        item['link'] = map(unicode.strip, site.xpath('a/@href').extract())
        item['desc'] = map(unicode.strip, site.xpath('text()').extract())
        items.append(item)
    print "hello"
    return items

而且它是有效的。我不确定它是什么，但我仍然在阅读unicode.strip。我希望这对你有所帮助

Answer 2

这是另一种方法(我使用了您的JSON数据)：

>>> data = {"desc": ["\r\n\t\t\t\r\n ", " \r\n\t\t\t\r\n - The primary goal of this book is to promote object-oriented design using Python and to illustrate the use of the emerging object-oriented design patterns.\r\nA secondary goal of the book is to present mathematical tools just in time. Analysis techniques and proofs are presented as needed and in the proper context.\r\n \r\n "], "link": ["http://www.brpreiss.com/books/opus7/html/book.html"], "title": ["Data Structures and Algorithms with Object-Oriented Design Patterns in Python"]}

>>> clean_data = ''.join(data['desc'])

>>> print clean_data.strip(' \r\n\t')

输出：

- The primary goal of this book is to promote object-oriented design using Python and to illustrate the use of the emerging object-oriented design patterns.
A secondary goal of the book is to present mathematical tools just in time. Analysis techniques and proofs are presented as needed and in the proper context.

而不是：

['\r\n\t\t\t\r\n ', ' \r\n\t\t\t\r\n - The primary goal of this book is to promote object-oriented design using Python and to illustrate the use of the emerging object-oriented design patterns.\r\nA secondary goal of the book is to present mathematical tools just in time. Analysis techniques and proofs are presented as needed and in the proper context.\r\n \r\n ']

Answer 3

假设您希望删除所有的\r、\n和\t (不仅仅是边缘上的东西)，同时仍然保留JSON的形式，您可以尝试以下操作：

def normalize_whitespace(json):
    if isinstance(json, str):
        return ' '.join(json.split())

    if isinstance(json, dict):
        it = json.items() # iteritems in Python 2
    elif isinstance(json, list):
        it = enumerate(json)

    for k, v in it:
        json[k] = normalize_whitespace(v)

    return json

用法：

>>> normalize_whitespace({"desc": ["\r\n\t\t\t\r\n ", " \r\n\t\t\t\r\n - The primary goal of this book is to promote object-oriented design using Python and to illustrate the use of the emerging object-oriented design patterns.\r\nA secondary goal of the book is to present mathematical tools just in time. Analysis techniques and proofs are presented as needed and in the proper context.\r\n \r\n "], "link": ["http://www.brpreiss.com/books/opus7/html/book.html"], "title": ["Data Structures and Algorithms with Object-Oriented Design Patterns in Python"]})
{'title': ['Data Structures and Algorithms with Object-Oriented Design Patterns in Python'], 'link': ['http://www.brpreiss.com/books/opus7/html/book.html'], 'desc': ['', '- The primary goal of this book is to promote object-oriented design using Python and to illustrate the use of the emerging object-oriented design patterns. A secondary goal of the book is to present mathematical tools just in time. Analysis techniques and proofs are presented as needed and in the proper context.']}

正如https://stackoverflow.com/a/10711166/138772提醒的那样，拆分-联接方法可能比正则表达式替换更好，因为它将strip功能与空格规范化结合在一起。