How to parse HTML table against a list of variables using lxml?

问题

I am trying to parse an HTML table using lxml. While rows = outhtml.xpath('//tr/td/span[@class="boldred"]/text()') fetches the results, I am trying to extract the column contents only when it starts with a variable in my config file. For instance, if a <td> starts with 'Street 1', I then want to grab the <span> contents of that <td> tag. This way, I can have a tuple of tuples (which takes care of the None values) which I can then store in the database.

lxml_parse.py

import lxml.html as lh

doc=open('test.htm', 'r')
outhtml=lh.parse(doc)
doc.close()

rows = outhtml.xpath('//tr/td/span[@class="boldred"]/text()')
print rows

test.htm

<tr>

    <td></td>

    <td colspan="2">

        Street 1:<span class="required"> *</span><br />

        <span class="boldred">2100 5th Ave</span>

    </td>

    <td colspan="2">

        Street 2:<br />

        <span class="boldred">Ste 202</span>

    </td>

</tr>

<tr>

    <td></td>

    <td>

        City:<span class="required"> *</span><br />

        <span class="boldred">NYC</span>

    </td>

    <td>

        State:<br />

        <SPAN CLASS="boldred2"></SPAN><br/><SPAN CLASS="boldred">NY</SPAN>

    </td>

    <td>

        Country:<span class="required"> *</span><br />

        <SPAN CLASS="boldred2"></SPAN><br/><SPAN CLASS="boldred">USA</SPAN>

    </td>

    <td>

        Zip:<br />

        <span class="boldred">10022</span>

    </td>

</tr>

Output :

$ python lxml_parse.py 
['2100 5th Ave', 'Ste 202', 'NYC', 'NY', 'USA', '10022']

Parse against a bunch of variables is what I am having problems with :

import lxml.html as lh

desiredvars = ['Street 1','Street 2','City', 'State', 'Zip']

doc=open('test.htm', 'r')
outhtml=lh.parse(doc)
doc.close()

myresultset = ((var, outhtml.xpath('//tr/td[child::*[text()=var]]/span[@class="boldred"]/text()')) for var in desiredvars)
print myresultset

回答1:

Aiming to produce this dictionary:

{'City:': 'NYC', 
 'Zip:': '10022', 
 'Street 1:': '2100 5th Ave', 
 'Country:': 'USA', 
 'State:': 'NY', 
 'Street 2:': 'Ste 202'}

You can use this code. And then it is easy to query the dictionary to get the values you desire:

import lxml.html as lh

test = '''<tr>
    <td></td>
    <td colspan="2">
        Street 1:<span class="required"> *</span><br />
        <span class="boldred">2100 5th Ave</span>
    </td>
    <td colspan="2">
        Street 2:<br />
        <span class="boldred">Ste 202</span>
    </td>
</tr>
<tr>
    <td></td>
    <td>
        City:<span class="required"> *</span><br />
        <span class="boldred">NYC</span>
    </td>
    <td>
        State:<br />
        <SPAN CLASS="boldred2"></SPAN><br/><SPAN CLASS="boldred">NY</SPAN>
    </td>
    <td>
        Country:<span class="required"> *</span><br />
        <SPAN CLASS="boldred2"></SPAN><br/><SPAN CLASS="boldred">USA</SPAN>
    </td>
    <td>
        Zip:<br />
        <span class="boldred">10022</span>
    </td>
</tr>'''

outhtml = lh.fromstring(test)
ks = [ k.strip() for k in outhtml.xpath('//tr/td/text()') if k.strip() != '' ]
vs = outhtml.xpath('//tr/td/span[@class="boldred"]/text()')

result = dict( zip(ks,vs) )

print result

回答2:

lxml_tempsofsol.py :

import lxml.html as lh

desiredvars = ['Street 1','Street 2','City', 'State', 'Zip']

doc=open('test.htm', 'r')
outhtml=lh.parse(doc)
doc.close()

myresultset = ((var, outhtml.xpath('//tr/td[contains(text(), "%s")]/span[@class="boldred"]/text()'%(var))[0]) for var in desiredvars)

for each in myresultset:
    print each

Output :

$ python lxml_tempsofsol.py
('Street 1', '2100 5th Ave')
('Street 2', 'Ste 202')
('City', 'NYC')
('State', 'NY')
('Zip', '10022')

回答3:

I've searched for the same thing and found your question and no "right" answer so I'll add a couple of points:

To refer to variables in XPath you should use $var syntax,
In lxml variables are passed as keyword arguments to xpath(),
Using child::* is wrong since you search for text directly within <td/>; text() already searches for text child nodes,
You need to use contains() XPath function due to whitespace.

Taking those into account your corrected code looks like this:

import lxml.html as lh

desiredvars = ['Street 1','Street 2','City', 'State', 'Zip']

doc=open('test.htm', 'r')
outhtml=lh.parse(doc)
doc.close()

myresultset = [(var, outhtml.xpath('//tr/td[contains(text(), $var)]/span[@class="boldred"]/text()', var=var)) for var in desiredvars]
print myresultset

来源：https://stackoverflow.com/questions/10642513/how-to-parse-html-table-against-a-list-of-variables-using-lxml

标签

html

lxml

python