使用Python ElementTree读取包含多个顶级项目的XML？

Question

如果XML有多个顶级项目，如何使用Python ElementTree读取XML文件？

我有一个XML文件，我想用Python ElementTree阅读。

不幸的是，它有多个顶级标签。我会将<doc>...</doc>包裹在XML周围，除非我必须在<doc>和<?xml>字段之后放置<!DOCTYPE> 。但找出<!DOCTYPE>结束的地方并非易事。

我有什么：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE FOO BAR "foo.dtd" [
<!ENTITY ...>
<!ENTITY ...>
<!ENTITY ...>
]>
<ARTICLE> ... </ARTICLE>
<ARTICLE> ... </ARTICLE>
<ARTICLE> ... </ARTICLE>
<ARTICLE> ... </ARTICLE>

我想要的是什么：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE FOO BAR "foo.dtd" [
<!ENTITY ...>
<!ENTITY ...>
<!ENTITY ...>
]>
<DOC>
<ARTICLE> ... </ARTICLE>
<ARTICLE> ... </ARTICLE>
<ARTICLE> ... </ARTICLE>
<ARTICLE> ... </ARTICLE>
</DOC>

注意标签ARTICLE的名称可能会改变，所以我不能为它而烦恼。

有人可以向我建议如何在XML标题后添加封闭的<doc>...</doc>，或建议其他解决方法吗？

Answer 1

我编写了以下函数来在 XML处理指令之后添加一个顶级标记。您现在可以在common Python library common.myelementtree.add_toplevel_tag

中找到此代码

import re
xmlprocre = re.compile("(\s*<[\?\!])")
def add_toplevel_tag(string):
    """
After all the XML processing instructions, add an enclosing top-level <DOC> tag, and return it.
e.g.
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE FOO BAR "foo.dtd" [ <!ENTITY ...> <!ENTITY ...> <!ENTITY ...> ]> <ARTICLE> ...
</ARTICLE> <ARTICLE> ... </ARTICLE> <ARTICLE> ... </ARTICLE> <ARTICLE> ... </ARTICLE>
=>
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE FOO BAR "foo.dtd" [ <!ENTITY ...> <!ENTITY ...> <!ENTITY ...> ]><DOC> <ARTICLE> ...
</ARTICLE> <ARTICLE> ... </ARTICLE> <ARTICLE> ... </ARTICLE> <ARTICLE> ... </ARTICLE></DOC>
"""
    def _advance_proc(string, idx):
        # If possible, advance over whitespace and one processing
        # instruction starting at string index idx, and return its index.
        # If not possible, return None
        # Find the beginning of the processing instruction
        m = xmlprocre.match(string[idx:])
        if m is None: return None
        #print "Group", m.group(1)
        idx = idx + len(m.group(1))
        #print "Remain", string[idx:]

        # Find closing > bracket
        bracketdebt = 1
        while bracketdebt > 0:
            if string[idx] == "<": bracketdebt += 1
            elif string[idx] == ">": bracketdebt -= 1
            idx += 1
        #print "Remain", string[idx:]
        return idx
    loc = 0
    while 1:
        # Advance one processing instruction
        newloc = _advance_proc(string, loc)
        if newloc is None: break
        else: loc = newloc
    return string[:loc] + "<DOC>" + string[loc:] + "</DOC>"