blocks|key|684866|text|Import[
++"http://en.wikipedia.org/wiki/Unemployment_by_country",
++"Data"]|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|684867|当然，结果经常需要进一步处理。您希望如何将其可视化？|unstyled|684868|您可以使用以下命令查找所有Import类型|offset|length|style|CODE|684869|Import[
++"http://en.wikipedia.org/wiki/Unemployment_by_country",
++"Elements"]|684870|entityMap^0|0|0|D|6|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|R|8|@]|9|@]|A|$]]|$1|G|3|H|5|F|7|S|8|@$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|V|8|@]|9|@]|A|$B|C]]|$1|O|3|-4|5|F|7|W|8|@]|9|@]|A|$]]]|P|$]]

<pre><code>Import[
 "http://en.wikipedia.org/wiki/Unemployment_by_country",
 "Data"]
</code></pre>

Of course, the result will frequently need further processing. How do you want to visualize it?

You can find all <code>Import</code> types using 

<pre><code>Import[
 "http://en.wikipedia.org/wiki/Unemployment_by_country",
 "Elements"]
</code></pre>

blocks|key|468901|text|虽然使用Import可能是一种更好、更健壮的方法，但我发现，至少对于这个特定的问题，我自己的HTML解析器(以this+thread发布)可以很好地进行少量的后处理。如果你从那里获取代码并执行它，使用这个函数来增强它：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|468902|Clear[findAndParseTables];
findAndParseTables[text_String]+:=
++Module[{parsed+=+postProcess@parseText[text]},
++++DeleteCases[
++++++Cases[parsed,+_tableContainer,+Infinity],
++++++_attribContainer+%7C+_spanContainer,+Infinity
++++]+//.
++++{(supContainer+%7C+tdContainer+%7C+trContainer+%7C+thContainer)[x___]+:>+{x},
++++++++iContainer[x___]+:>+x,
++++++++aContainer[x_]+:>+x,
++++++++"\n"+:>+Sequence[],
+++++++divContainer[]+%7C+ulContainer[]+%7C+liContainer[]+%7C+aContainer[]+:>+Sequence[]}];|code-block|syntax|javascript|468903|然后，我认为，您可以通过下面的代码获得相当完整的数据：|468904|text+=+Import["http://en.wikipedia.org/wiki/Unemployment_by_country",+"Text"];
myData+=+First@findAndParseTables[text];|468905|下面是结果的外观：|468906|In[92]:=+Short[myData,5]
Out[92]//Short=+
tableContainer[{{Country+/+Region},{Unemployment+rate+(%25)},{Source+/+date+of+information}},
{{Afghanistan},{35.0},{2008,{3}}},{{Albania},{13.49},{2010+(Q4),{4}}},
{{Algeria},{10.0},{2010+(September),{5}}},<<188>>,{{West+Bank},{17.2},{2010,{43}}},
{{Yemen},{35.0},{2009+(June),{128}}},{{Zambia},{16.0},{2005,{129}}},{{Zimbabwe},{97.0},{2009}}]|468907|我喜欢这种方法(而不是Import->XMLObject)的原因是，因为我用最少的语法将网页转换成数学表达式(不像XML对象)，通常很容易建立一组替换规则，在每种给定的情况下都能进行正确的后处理。最后一个免责声明是，我的解析器并不健壮，并且肯定包含许多错误，因此请注意。|468908|entityMap|0|LINK|mutability|MUTABLE|url|http://groups.google.com/group/comp.soft-sys.math.mathematica/browse_thread/thread/8cc202181435104c^0|4|6|1J|B|0|0|0|0|0|0|0|B|H|0^^$0|@$1|2|3|4|5|6|7|12|8|@$9|13|A|14|B|C]]|D|@$9|15|A|16|1|17]]|E|$]]|$1|F|3|G|5|H|7|18|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|19|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|1A|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|1B|8|@]|D|@]|E|$]]|$1|Q|3|R|5|H|7|1C|8|@]|D|@]|E|$I|J]]|$1|S|3|T|5|6|7|1D|8|@$9|1E|A|1F|B|C]]|D|@]|E|$]]|$1|U|3|-4|5|6|7|1G|8|@]|D|@]|E|$]]]|V|$W|$5|X|Y|Z|E|$10|11]]]]

While the use of <code>Import</code> is probably a better and more robust way, I found that, at least for this particular problem, my own HTML parser (published in <a href="http://groups.google.com/group/comp.soft-sys.math.mathematica/browse_thread/thread/8cc202181435104c" rel="noreferrer">this thread</a>), works fine with a small amount of post-processing. If you take the code from there and execute it, augmenting it with this function:

<pre><code>Clear[findAndParseTables];
findAndParseTables[text_String] :=
 Module[{parsed = postProcess@parseText[text]},
 DeleteCases[
 Cases[parsed, _tableContainer, Infinity],
 _attribContainer | _spanContainer, Infinity
 ] //.
 {(supContainer | tdContainer | trContainer | thContainer)[x___] :&gt; {x},
 iContainer[x___] :&gt; x,
 aContainer[x_] :&gt; x,
 "\n" :&gt; Sequence[],
 divContainer[] | ulContainer[] | liContainer[] | aContainer[] :&gt; Sequence[]}];
</code></pre>

Then you get, I think, a pretty much complete data by this code:

<pre><code>text = Import["http://en.wikipedia.org/wiki/Unemployment_by_country", "Text"];
myData = First@findAndParseTables[text];
</code></pre>

Here is how the result looks:

<pre><code>In[92]:= Short[myData,5]
Out[92]//Short= 
tableContainer[{{Country / Region},{Unemployment rate (%)},{Source / date of information}},
{{Afghanistan},{35.0},{2008,{3}}},{{Albania},{13.49},{2010 (Q4),{4}}},
{{Algeria},{10.0},{2010 (September),{5}}},&lt;&lt;188&gt;&gt;,{{West Bank},{17.2},{2010,{43}}},
{{Yemen},{35.0},{2009 (June),{128}}},{{Zambia},{16.0},{2005,{129}}},{{Zimbabwe},{97.0},{2009}}]
</code></pre>

What I like about this approach (as opposed to say, <code>Import-&gt;XMLObject</code>) is that, since I convert the web page into Mathematica expression with minimal syntax (unlike e.g. XML objects), it is often very easy to establish a set of replacement rules which does the right post-processing in each given case. A final disclaimer is that my parser is not robust and does for sure contain a number of bugs, so be warned.

blocks|key|468999|text|如果你想导入...，"XMLObject“路线，这是你可以做的概述。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|469000|首先，获取页面：|469001|page+=+Import["http://en.wikipedia.org/wiki/Unemployment_by_country",+"XMLObject"];|code-block|syntax|javascript|469002|接下来，获取感兴趣的表(在本例中，大表恰好也是此页面上七个表中的第一个)：|469003|table+=+Cases[page,+XMLElement["table",+___],+\[Infinity]][[1]]|469004|接下来，从table中获取一个row，我选择了对应于阿尔及利亚的第四行：|offset|length|style|CODE|469005|row+=Cases[表，XMLElement"tr"，___，无穷大][4]|469006|接下来，从该行提取表数据元素()：|469007|data+=+Cases[row,+XMLElement["td",+___],+\[Infinity]]|469008|例如，您可以从这些元素中选取国家国旗缩略图，如下所示：|469009|image+=+Cases[data,+XMLElement["img",+{___,+"src"+->+src_,+___},+_]+:>+src,+\[Infinity]]|469010|最后导入图像缩略图(由于某种原因，需要在前面加上"http:“)：|469011|Import["http:"+<>+image]|469012|这是笔记本的外观(缩略图加上其他输入)：|469013|​|469014|📷|atomic|469015|469016|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/f12569d2a7ec70bf1cc9c84f62c7a88c.png|imageAlt^0|0|0|0|0|0|5|5|F|3|0|0|0|0|0|0|0|0|0|0|0|1|0|0|0^^$0|@$1|2|3|4|5|6|7|1N|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|1O|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|1P|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|1Q|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|1R|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|1S|8|@$O|1T|P|1U|Q|R]|$O|1V|P|1W|Q|R]]|9|@]|A|$]]|$1|S|3|T|5|6|7|1X|8|@]|9|@]|A|$]]|$1|U|3|V|5|6|7|1Y|8|@]|9|@]|A|$]]|$1|W|3|X|5|F|7|1Z|8|@]|9|@]|A|$G|H]]|$1|Y|3|Z|5|6|7|20|8|@]|9|@]|A|$]]|$1|10|3|11|5|F|7|21|8|@]|9|@]|A|$G|H]]|$1|12|3|13|5|6|7|22|8|@]|9|@]|A|$]]|$1|14|3|15|5|F|7|23|8|@]|9|@]|A|$G|H]]|$1|16|3|17|5|6|7|24|8|@]|9|@]|A|$]]|$1|18|3|19|5|6|7|25|8|@]|9|@]|A|$]]|$1|1A|3|1B|5|1C|7|26|8|@]|9|@$O|27|P|28|1|29]]|A|$]]|$1|1D|3|19|5|6|7|2A|8|@]|9|@]|A|$]]|$1|1E|3|-4|5|6|7|2B|8|@]|9|@]|A|$]]]|1F|$1G|$5|1H|1I|1J|A|$1K|1L|1M|-4]]]]

If you want to go the Import[ ... , "XMLObject" ] route, here is an outline of what you can do.

First, get the page:

<pre><code>page = Import["http://en.wikipedia.org/wiki/Unemployment_by_country", "XMLObject"];
</code></pre>

Next, get the table of interest (in this case the big table also happens to be the first of seven tables on this page):

<pre><code>table = Cases[page, XMLElement["table", ___], \[Infinity]][[1]]
</code></pre>

Next, get a <code>row</code> from the <code>table</code>, I picked the fourth row which corresponds with Algeria:

row = Cases[table, XMLElement["tr", ___], [Infinity]][[4]]

Next, extract the table data elements () from this row:

<pre><code>data = Cases[row, XMLElement["td", ___], \[Infinity]]
</code></pre>

Out of those elements, you can pick for example the country flag thumbnail, like so:

<pre><code>image = Cases[data, XMLElement["img", {___, "src" -&gt; src_, ___}, _] :&gt; src, \[Infinity]]
</code></pre>

Finally import that image thumbnail (it needed "http:" prepended for some reason):

<pre><code>Import["http:" &lt;&gt; image]
</code></pre>

This is what the notebook looks like (the thumbnail, plus the other inputs):

<img src="https://i.stack.imgur.com/jxUpi.png" alt="Mathematica graphics">

Is there an easy way to extract data from specific HTML tables using Mathematica? <code>Import</code> seems to be pretty powerful, and Mathematica appears to be capable of handling formats such as XML pretty well.

Here's an example: <a href="http://en.wikipedia.org/wiki/Unemployment_by_country">http://en.wikipedia.org/wiki/Unemployment_by_country</a>

Extract information from HTML using Mathematica

有没有一种简单的方法可以使用Mathematica从特定的超文本标记语言表格中提取数据呢？Import似乎非常强大，而且Mathematica似乎能够很好地处理诸如XML之类的格式。下面是一个例子：

问使用Mathematica从HTML中提取信息
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