使用Scrapy从字符串中提取数据

Question

<string xmlns="http://schemas.microsoft.com/2003/10/Serialization/">
{"InstrumentID":85,"BuyPrice":24677.0,"SellPrice":24671.0,"HighPrice":24671.0,"LowPrice":24212.0,"ChangePercent":2.1,"ChangePercentText":"2.10%","UsersBuyPercentage":56.0,"UsersSellPercentage":44.0,"IsValid":true}
</string>

我需要提取买价，卖价与刮，但我不知道如何。有人能帮忙吗？你知道吗

Answer 1

看起来xml中有json，因此提取数据将分为两部分：

1. 提取json字符串
2. 使用json模块加载所需的信息

如何做到这一点的示例（此处使用scrapy shell）：

>>> import json
>>> sel = scrapy.Selector(text='''<string xmlns="http://schemas.microsoft.com/2003/10/Serialization/">
... {"InstrumentID":85,"BuyPrice":24677.0,"SellPrice":24671.0,"HighPrice":24671.0,"LowPrice":24212.0,"ChangePercent":2.1,"ChangePercentText":"2.10%","UsersBuyPercentage":56.0,"UsersSellPercentage":44.0,"IsValid":true}
... </string>''')
>>> sel.remove_namespaces()
>>> json.loads(sel.xpath('//string/text()').get())
{'InstrumentID': 85, 'BuyPrice': 24677.0, 'SellPrice': 24671.0, 'HighPrice': 24671.0, 'LowPrice': 24212.0, 'ChangePercent': 2.1, 'ChangePercentText': '2.10%', 'UsersBuyPercentage': 56.0, 'UsersSellPercentage': 44.0, 'IsValid': True}