Question

我有以下html要废弃

<h2>
  <span id="title">Title</span>
</h2>
<p>Content 1</p>
<p>Content 2</p>
<p>Content 3</p>
<p>Content 4</p>
<h2>Some other header</h2>
<p>Do not want this content</p>

我想要选择的是标题后面的一系列4个<p>标记，并在遇到非<p>标记后立即忽略其他所有标记。

到目前为止，我的xpath是//h2[span[@id='title']]/following-sibling::p，但这也包含不需要的

标签。

我也试过了前面的兄弟方法而没有运气//p[preceding-sibling::h2[span[@id='title']]]。额外的<p>标记仍然包含在内。

Answer 1

试试这个xpath：

//p[preceding-sibling::h2[1][./span[@id = 'title']]]

这个xpath做了什么：它会搜索p元素，这些元素具有h2个元素作为前一个兄弟姐妹但在一个条件下 - 只有当他们的第一个前兄弟h2有一个名为span的子元素且属性为{{ 1}}等于id

为何过滤title？：因为列出的<p>Do not want this content</p>之前的p出现在订单中：

h2

<h2>Some other header</h2>

因此<h2> <span id="title">Title</span> </h2>被证明是错误的，因此不会返回此h2[1][./span[@id = 'title']]。

示例xml上的结果：

是：

<root>
<h2>
  <span id="title">Title</span>
</h2>
<p>Content 1</p>
<p>Content 2</p>
<p>Content 3</p>
<p>Content 4</p>
<h2>Some other header</h2>
<p>Do not want this content</p>
<p>Do not want this content too</p>
</root>

Answer 2

我建议你使用BeautifulSoup。

03:40:29.7147 start 10
03:40:29.7304 start 9
03:40:29.7304 start 8
03:40:29.7459 start 7
03:40:29.7459 start 6
03:40:29.7616 start 5
03:40:29.7772 start 4
03:40:29.7772 start 3
03:40:29.7928 start 2
03:40:29.7928 start 1

03:40:35.3067 start sleep 7
03:40:35.3067 start sleep 8
03:40:35.3067 start sleep 9
03:40:35.3692 start sleep 10
03:40:35.4629 start sleep 6

03:40:45.3292 end sleep 7 diff 10022.5353
03:40:45.3292 end sleep 8 diff 10022.5353
03:40:45.3292 end sleep 9 diff 10022.5353
03:40:45.3761 end sleep 10 diff 10006.8765
03:40:45.4855 end sleep 6 diff 10022.5243
03:40:45.3605 end 9 diff 15630.1005
03:40:45.3917 end 7 diff 15645.7465
03:40:45.3917 end 8 diff 15661.3313
03:40:45.4229 end 10 diff 15708.2274
03:40:45.5323 end 6 diff 15786.3969
03:40:45.4386 start sleep 5
03:40:45.4542 start sleep 4
03:40:45.4542 start sleep 3
03:40:45.4698 start sleep 2
03:40:45.5636 start sleep 1
03:40:45.4698 start 11
03:40:45.4855 start 12
03:40:45.5011 start 13
03:40:45.5167 start 14
03:40:45.6105 start 15

03:40:55.4596 end sleep 3 diff 10005.4374
03:40:55.4596 end sleep 4 diff 10005.4374
03:40:55.4596 end sleep 5 diff 10021.0426
03:40:55.4752 end sleep 2 diff 10005.3992
03:40:55.5690 end sleep 1 diff 10005.3784
03:40:55.4752 end 3 diff 25698.0221
03:40:55.4909 end 5 diff 25729.302
03:40:55.5065 end 4 diff 25729.2523
03:40:55.5221 end 2 diff 25729.2559
03:40:55.6159 end 1 diff 25823.032
03:40:55.5534 start sleep 11
03:40:55.5534 start sleep 12
03:40:55.5690 start sleep 13
03:40:55.5846 start sleep 14
03:40:55.6784 start sleep 15
03:40:55.6002 start 16
03:40:55.6002 start 17
03:40:55.6159 start 18
03:40:55.6326 start 19
03:40:55.7096 start 20

03:41:05.5692 end sleep 11 diff 10015.8226
03:41:05.5692 end sleep 12 diff 10015.8226
03:41:05.5848 end sleep 13 diff 10015.8108
03:41:05.6004 end sleep 14 diff 10015.8128
03:41:05.6942 end sleep 15 diff 10015.8205
03:41:05.5848 end 12 diff 20099.3218
03:41:05.6004 end 11 diff 20130.5719
03:41:05.6161 end 13 diff 20114.9729
03:41:05.6473 end 14 diff 20130.5962
03:41:05.6942 end 15 diff 20083.7506
03:41:05.6317 start sleep 17
03:41:05.6317 start sleep 16
03:41:05.6473 start sleep 18
03:41:05.6629 start sleep 19
03:41:05.7411 start sleep 20

03:41:15.6320 end sleep 16 diff 10000.3608
03:41:15.6320 end sleep 17 diff 10000.3608
03:41:15.6477 end sleep 18 diff 10000.3727
03:41:15.6633 end sleep 19 diff 10000.3709
03:41:15.7414 end sleep 20 diff 10000.3546
03:41:15.6477 end 16 diff 20047.4375
03:41:15.6477 end 17 diff 20047.4375
03:41:15.6633 end 18 diff 20047.4295
03:41:15.7101 end 19 diff 20077.5169
03:41:15.7414 end 20 diff 20031.7909

在Scrapy中选择下一个兄弟姐妹的序列

2 个答案: