Question

我有一个包含超过10万行的txt文件，并且我想为每一行创建一个XML树。但是所有行都共享相同的根。

这里是txt文件：

LIBRARY:
1,1,1,1,the
1,2,1,1,world
2,1,1,2,we
2,5,2,1,have
7,3,1,1,food

所需的输出：

   <LIBRARY>
    <BOOK ID ="1">
        <CHAPTER ID ="1">
            <SENT ID ="1">
                <WORD ID ="1">the</WORD>
            </SENT>
        </CHAPTER>
    </BOOK>
    <BOOK ID ="1">
        <CHAPTER ID ="2">
            <SENT ID ="1">
                <WORD ID ="1">world</WORD>
            </SENT>
        </CHAPTER>
    </BOOK>
    <BOOK ID ="2">
        <CHAPTER ID ="1">
            <SENT ID ="1">
                <WORD ID ="2">we</WORD>
            </SENT>
        </CHAPTER>
    </BOOK>
    <BOOK ID ="2">
        <CHAPTER ID ="5">
            <SENT ID ="2">
                <WORD ID ="1">have</WORD>
            </SENT>
        </CHAPTER>
    </BOOK>
    <BOOK ID ="7">
        <CHAPTER ID ="3">
            <SENT ID ="1">
                <WORD ID ="1">food</WORD>
            </SENT>
        </CHAPTER>
    </BOOK>
</LIBRARY>

我使用Element树将txt文件转换为xml文件，这是我运行的代码

def expantree():
  lines = txtfile.readlines()
  for line in lines:
    split_line = line.split(',')
    BOOK.set( 'ID ', split_line[0])
    CHAPTER.set( 'ID ', split_line[1])
    SENTENCE.set( 'ID ', split_line[2])
    WORD.set( 'ID ', split_line[3])
    WORD.text = split_line[4]
    tree = ET.ElementTree(Root)
    tree.write(xmlfile)

好的，代码正在运行，但我没有得到所需的输出，我得到了以下内容：

<LIBRARY>
    <BOOK ID ="1">
        <CHAPTER ID ="1">
            <SENT ID ="1">
                <WORD ID ="1">the</WORD>
            </SENT>
        </CHAPTER>
    </BOOK>
</LIBRARY>
<LIBRARY>
    <BOOK ID ="1">
        <CHAPTER ID ="2">
            <SENT ID ="1">
                <WORD ID ="1">world</WORD>
            </SENT>
        </CHAPTER>
    </BOOK>
</LIBRARY>
<LIBRARY>
    <BOOK ID ="2">
        <CHAPTER ID ="1">
            <SENT ID ="1">
                <WORD ID ="2">we</WORD>
            </SENT>
        </CHAPTER>
    </BOOK>
</LIBRARY>
<LIBRARY>
    <BOOK ID ="2">
        <CHAPTER ID ="5">
            <SENT ID ="2">
                <WORD ID ="1">have</WORD>
            </SENT>
        </CHAPTER>
    </BOOK>
</LIBRARY>
<LIBRARY>
    <BOOK ID ="7">
        <CHAPTER ID ="3">
            <SENT ID ="1">
                <WORD ID ="1">food</WORD>
            </SENT>
        </CHAPTER>
    </BOOK>
</LIBRARY>

如何统一树根，所以我得到一个root标签而不是获得多个root标签？

Answer 1

另一个可能更简洁的选择如下：

from xml.etree import ElementTree as ET
import io
import os

# Setup the test input
inbuf = io.StringIO(''.join(['LIBRARY:\n', '1,1,1,1,the\n', '1,2,1,1,world\n',
                             '2,1,1,2,we\n', '2,5,2,1,have\n', '7,3,1,1,food\n']))

tags = ['BOOK', 'CHAPTER', 'SENT', 'WORD']
with inbuf as into, io.StringIO() as xmlfile:
    root_name = into.readline()
    root = ET.ElementTree(ET.Element(root_name.rstrip(':\n')))
    re = root.getroot()
    for line in into:
        values = line.split(',')
        parent = re
        for i, v in enumerate(values[:4]):
            parent =  ET.SubElement(parent, tags[i], {'ID': v})
            if i == 3:
                parent.text = values[4].rstrip(':\n')
    root.write(xmlfile, encoding='unicode', xml_declaration=True)
    xmlfile.seek(0, os.SEEK_SET)
    for line in xmlfile:
        print(line)

此代码的作用是从输入数据构造ElementTree并将其作为XML文件写入类文件对象。此代码可以使用标准Python xml.etree包或lxml。代码使用Python 3.3进行测试。

Answer 2

这是一个使用lxml（使用Python 2.7测试）的建议。代码也很容易适应与ElementTree一起使用，但是很难获得漂亮的漂亮打印输出（有关此内容的更多内容，请参阅https://stackoverflow.com/a/16377996/407651。）

输入文件是library.txt，输出文件是library.xml。

from lxml import etree

lines = open("library.txt").readlines()
library = etree.Element('LIBRARY')   # The root element 

# For each line with data in the input file, create a BOOK/CHAPTER/SENT/WORD structure
for line in lines:
    values = line.split(',')
    if len(values) == 5:
        book = etree.SubElement(library, "BOOK")
        book.set("ID", values[0])
        chapter = etree.SubElement(book, "CHAPTER")
        chapter.set("ID", values[1])
        sent = etree.SubElement(chapter, "SENT")
        sent.set("ID", values[2])
        word = etree.SubElement(sent, "WORD")
        word.set("ID", values[3])
        word.text = values[4].strip()

etree.ElementTree(library).write("library.xml", pretty_print=True)

Answer 3

一种方法是创建完整的树并打印它。我使用了以下代码：

from lxml import etree as ET

def create_library(lines):
    library = ET.Element('LIBRARY')
    for line in lines:
        split_line = line.split(',')
        library.append(create_book(split_line))
    return library

def create_book(split_line):
    book = ET.Element('BOOK',ID=split_line[0])
    book.append(create_chapter(split_line))
    return book

def create_chapter(split_line):
    chapter = ET.Element('CHAPTER',ID=split_line[1])
    chapter.append(create_sentence(split_line))
    return chapter

def create_sentence(split_line):
    sentence = ET.Element('SENT',ID=split_line[2])
    sentence.append(create_word(split_line))
    return sentence

def create_word(split_line):
    word = ET.Element('WORD',ID=split_line[3])
    word.text = split_line[4]
    return word

然后您创建文件的代码如下所示：

def expantree():
    lines = txtfile.readlines()
    library = create_library(lines)
    ET.ElementTree(lib).write(xmlfile)

如果您不想在内存中加载整个树（您提到有超过10万行），您可以手动创建标记，一次编写一本书，然后添加标记。在这种情况下，您的代码将如下所示：

def expantree():
    lines = txtfile.readlines()
    f = open(xmlfile,'wb')
    f.write('<LIBRARY>')
    for line in lines:
        split_line = line.split(',')
        book = create_book(split_line)
        f.write(ET.tostring(book))
    f.write('</LIBRARY>')
    f.close()

我对lxml没有太多经验，所以可能有更优雅的解决方案，但这两种方法都有效。

在python中使用For循环创建一个xml文件

3 个答案: