I'm trying to parse a html page and extract 2 values from a table row. The html for the table row is as follows: -
<tr>
<td title="Associated temperature in (ºC)" class="TABLEDATACELL" nowrap="nowrap" align="Left" colspan="1" rowspan="1">Max Temperature (ºC)</td>
<td class="TABLEDATACELLNOTT" nowrap="nowrap" align="Center" colspan="1" rowspan="1">6</td>
<td class="TABLEDATACELLNOTT" nowrap="nowrap" align="Center" colspan="1" rowspan="1"> 13:41:30</td>
</tr>
and the expression I have at the moment is:
<tr>[\s]<td[^<]+?>Max Temperature[\w\s]*</td>[\s]
<td[^<]+?>(?<value>([\d]+))</td>[\s]
<td[^<]+?>(?<time>([\d\:]+))</td>[\s]</tr>
However I don't seem to be able to extract any matches. Could anyone point me in the right direction, thanks.
Parsing HTML reliably using regexp is known to be notoriously difficult.
I think I would be looking for a HTML parsing library, or a "screen scraping" library ;)
If the HTML comes from an unreliable source, you have to be extra careful to handle malicious HTML syntax well. Bad HTML handling is a major source of security attacks.
Try
<tr>\s*
<td[^>]*>.*?</td>\s*
<td[^>]*>\s*(?<value>\d+)\s*</td>\s*
<td[^>]*>\s*(?<time>\d{2}:\d{2}:\d{2})\s*</td>\s*
</tr>\s*
When you write <td[^<]+?>
I guess you really mean <td[^>]*>
That is "opening brace, td, maybe stuff other than closing brace..."
<tr>[\s]<td[^<]+?>Max Temperature[\w\s]*</td>[\s]
还没有看完它,但是[^ <]可能需要[^>],因为你试图匹配所有非>直到>在最高温度之前。
The " (ºC)" before the closing td was matched against:
<tr>[\s]<td[^<]+?>Max Temperature[^<]*</td>[\s]
Is that \\wa word-boundary? I think that it gets a little tricky there, I'd use a more general approach.
And on the third line, there is one whitespace after the td tag, is that accounted for?
<td[^<]+?>[\s]?(?<time>([\d\:]+))</td>[\s]</tr>
I use http://www.regexbuddy.com/ for such controls. So far I tested @sgehrig's suggestion is correct
Use the Html Agility Pack or a similar library instead, as @Bjarke Ebert suggests. It's the right tool for the task.
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