<table class="tabledataformat" cellspacing="0" >
<tr>
<td style="vertical-align:top;">Copper, Cu </td>
<td class="dataCell" style="vertical-align:top;"><= 0.03 %<span class="dataCondition"></span></td>
<td class="dataCell" style="vertical-align:top;"><= 0.03 %<span class="dataCondition"></span></td>
<td class="dataComment" style="vertical-align:top;"></td>
</tr>
</table>
response.xpath('//table[@class="tabledataformat"]/tr').extract() 只能获取到
<tr>
<td style="vertical-align:top;">Copper, Cu </td>
<td class="dataCell" style="vertical-align:top;"></td>
<td class="dataCell" style="vertical-align:top;"></td>
<td class="dataComment" style="vertical-align:top;"></td>
</tr>
<= 0.03 % 和 消失不见,为什么呢?