某次，对于字符串
footerUni=u"分类： | 标签：";
使用：
foundCatZhcn = re.search(u"分类：(?P<catName>.+)|", footerUni);
print "foundCatZhcn=",foundCatZhcn;
if(foundCatZhcn):
print "foundCatZhcn.group(0)=",foundCatZhcn.group(0);
print "foundCatZhcn.group(1)=",foundCatZhcn.group(1);
catName = foundCatZhcn.group("catName");
print "catName=",catName;
所得到的结果却是：
foundCatZhcn= <_sre.SRE_Match object at 0x027E3C20>
foundCatZhcn.group(0)=
foundCatZhcn.group(1)= None
catName= None
其中group(0)，不是所期望的整个匹配的字符串，且group(1)应该是一个空格的字符，而不是None。
调试了半天，最后终于找到原因了，原来是在正则搜索中，竖线"|"，是or的关系
“'|'
A|B, where A and B can be arbitrary REs, creates a regular expression that will match either A or B. An arbitrary number of REs can be separated by the '|' in this way. This can be used inside groups (see below) as well. As the target string is scanned, REs separated by '|' are tried from left to right. When one pattern completely matches, that branch is accepted. This means that once A matches, B will not be tested further, even if it would produce a longer overall match. In other words, the '|' operator is never greedy. To match a literal '|', use \|, or enclose it inside a character class, as in [|].
”所以此处匹配到的结果是空值
所以测试过程中，无论如何修改re中的表达式，也都会得到foundCatZhcn是非空的值
然后对应的解决办法是，给竖线加上反斜杠，表示竖线字符本身：
foundCatZhcn = re.search(u"分类：(?P<catName>.*?)\|", footerUni);
这样才能真正自己想要的效果。
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| 第 6 章 Python中正则表达式的使用心得 |  | 6.2. re模块的search的含义和用法及查找后group的含义 |
