在XPath中选择相反条件？

Question

I have below XML

<Root>
    <Element>
        <batch_id>Jan_22_2021_18</batch_id>
        <proposal_id>130994</proposal_id>
        <proposal_name>Brazil </proposal_name>
        <subregion>1234</subregion>
        <currency>BRL</currency>
    </Element>
    <Element>
        <batch_id>Jan_22_2021_18</batch_id>
        <proposal_id>130994</proposal_id>
        <proposal_name>Brazil </proposal_name>
        <subregion>7225</subregion>
        <currency>BRL</currency>
    </Element>
        <Element>
        <batch_id>Jan_22_2021_18</batch_id>
        <proposal_id>130994</proposal_id>
        <proposal_name>Brazil </proposal_name>
        <subregion>1111</subregion>
        <currency>BRL</currency>
    </Element>
</Root>

以下是XPath

1. Working:

   /Root/Element[(subregion ='7515') or (subregion ='7225') or (subregion ='1234') or (subregion ='8360') or (subregion ='8385') or (subregion ='8435') or (subregion ='8585')]
   

2. Not working

   /Root/Element[(subregion !='7515') or (subregion !='7225') or (subregion !='1234') or (subregion !='8360') or (subregion !='8385') or (subregion !='8435') or (subregion !='8585')]
   

你能解释一下为什么吗？

- Yatan

Answer 1

您有一个逻辑错误。 < p > < /p >

“A或B”的相反是不是“not(A)或not(B)”，而是“not(A或B)”，或者根据De Morgan的等价性，“not(A) and not(B)”。

因此，如果您希望其他未被您的“工作”XPath选择的 Elements 应用逻辑 not（）到整个析取上，

/Root/Element[not((subregion ='7515') 
               or (subregion ='7225') 
               or (subregion ='1234') 
               or (subregion ='8360') 
               or (subregion ='8385') 
               or (subregion ='8435') 
               or (subregion ='8585'))]

或者根据相应连词的个别条件：

/Root/Element[    not(subregion ='7515') 
              and not(subregion ='7225') 
              and not(subregion ='1234') 
              and not(subregion ='8360') 
              and not(subregion ='8385') 
              and not(subregion ='8435') 
              and not(subregion ='8585')]

- kjhughes

---

但是他没有使用 not(X = 'abc')，而是使用 X != 'abc'，在XPath中这两者并不相同；虽然在这种情况下这不是问题的原因，因为 subregion 总是选择单例，但应该解释一下。 - Michael Kay

虽然这里不是问题，但@MichaelKay正确指出未来的读者也应该知道XPath中not(X = 'abc')和X != 'abc'是不同的。请参见Dimitre在此处的答案或其他几个Q/A（例如这里或这里），涵盖了这个特定概念。 - kjhughes