Scrapy 中 xpath 用到中文报错

[donglongtu]

问题描述

links = sel.xpath('//i[contains(@title,"置顶")]/following-sibling::a/@href').extract()

报错：ValueError: All strings must be XML compatible: Unicode or ASCII, no NULL bytes or control characters

[revotu]

参见文章：[解决 Scrapy 中 xpath 用到中文报错问题][1]

## 解决方法 ##
方法一：将整个 xpath 语句转成 Unicode
```Python
links = sel.xpath(u'//i[contains(@title,"置顶")]/following-sibling::a/@href').extract()
```
方法二：xpath 语句用已转成 Unicode 的 title 变量
```Python
title = u"置顶"
links = sel.xpath('//i[contains(@title,"%s")]/following-sibling::a/@href' %(title)).extract()
```
方法三：直接用 xpath 中变量语法(`$`符号加变量名)`$title`, 传参 title 即可
```Python
links = sel.xpath('//i[contains(@title,$title)]/following-sibling::a/@href', title="置顶").extract()
```


[1]: http://www.revotu.com/solve-unicode-erros-using-xpath-in-scrapy.html

[bsns]

我一般是加 u

[mingyun]

@revotu nice

[NaVient]

独立爬虫项目，请用 py3