为什么这个条件应该执行为真时执行为假? [英] Why does this condition execute to false when it should execute to true?

问题描述

我的蜘蛛 basic.py 文件中有此代码:

I have this code in my spider basic.py file:

if l.add_xpath('price', '//*[@id="price"]/text()',
            MapCompose(lambda i: i.replace(',', ''), float),
            re = '[,.0-9]'):
    l.add_value('available', 1)
else:
    l.add_value('price', 0)
    l.add_value('available', 0)

当找到价格时，预期结果是 available = 1，但我得到的是 0，我不明白为什么！

The expected result is available = 1 when there is a price found, but what I get is 0 and I don't understand why!

有什么想法吗?

推荐答案

以防万一有人遇到同样的情况:

Just in case someone ran into the same situation:

答案是 add_xpath 不返回任何东西，为了检查是否找到元素，应该使用 get_xpath 代替(见这里).

The answer is that add_xpath does not return anything, and in order to check whether there is an element found or not, get_xpath should be used instead (see here).

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