Question

def parse_header(table):
    ths = table.xpath('//tr/th')
    if not ths:
        ths = table.xpath('//tr[1]/td') # here is the problem, this will find tr[1]/td in all html file insted of this table

    # bala bala something elese

doc = html.fromstring(html_string)
table = doc.xpath("//div[@id='divGridData']/div[2]/table")[0]
parse_header(table)

我想在我的表中找到所有tr[1]/td，但table.xpath("//tr[1]/td")仍在html文件中找到所有内容。我怎样才能找到这个元素而不是所有的html文件？

编辑：

    content = '''

<root>
    <table id="table-one">
        <tr>
            <td>content from table 1</td>
        <tr>
        <table>
             <tr>
                 <!-- this is content I do not want to get -->
                <td>content from embeded table</td>
            <tr>
        </table>
    </table>
</root>'''

root = etree.fromstring(content)
table_one = root.xpath('table[@id="table-one"]')
all_td_elements = table_one.xpath('//td') # so this give me too much!!!

现在我不想要嵌入表格内容，我该怎么做？

Answer 1

要查找作为上下文节点的子元素的元素，请将句点.运算符添加到XPath中。所以，我认为您正在寻找的XPath是：

.//tr[1]/td

这将选择作为当前表的子元素的td元素，而不是整个HTML文件。

举个例子：

from lxml import etree

content = '''

<root>
    <table id="table-one">
        <tr>
            <td>content from table 1</td>
        <tr>
    </table>
    <table id="table-two">
        <tr>
            <td>content from table 2</td>
        <tr>
    </table>
</root>'''

root = etree.fromstring(content)
table_one = root.xpath('table[@id="table-one"]')

# this will select all td elements in the entire XML document (so two elements)
all_td_elements = table_one.xpath('//td') 

# this will just select the single sub-element because of the period
just_sub_td_elements = table_one.xpath('.//td')

使用xpath查找表元素中的所有tr？

1 个答案: