使用 xml.dom.minidom 更新元素值

Question

我有一个 XML 结构，看起来类似于：

<Store>
   <foo>
      <book>
        <isbn>123456</isbn>
      </book>
      <title>XYZ</title>
      <checkout>no</checkout>
   </foo>

   <bar>
      <book>
        <isbn>7890</isbn>
      </book>
      <title>XYZ2</title>
      <checkout>yes</checkout>
   </bar>
</Store>

仅使用 xml.dom.minidom（限制） 我想

1）遍历 XML 文件

2）搜索/获取特定元素，具体取决于其父元素

示例：author1 的 checkout 元素，isbn 为author2

3）更改/设置该元素的值

4）将新的XML 结构写入文件

有人可以帮忙吗？

谢谢你！

更新：

这就是我到目前为止所做的

import xml.dom.minidom
checkout = "yes"

def getLoneChild(node, tagname):

  assert ((node is not None) and (tagname is not None))
  elem = node.getElementsByTagName(tagname)
  if ((elem is None) or (len(elem) != 1)):
    return None
  return elem

def getLoneLeaf(node, tagname):

  assert ((node is not None) and (tagname is not None))
  elem = node.getElementsByTagName(tagname)
  if ((elem is None) or (len(elem) != 1)):
    return None
  leaf = elem[0].firstChild
  if (leaf is None):
    return None
  return leaf.data


def setcheckout(node, tagname):

  assert ((node is not None) and (tagname is not None))
  child = getLoneChild(node, 'foo')
  Check = getLoneLeaf(child[0],'checkout')
  Check = tagname
  return Check

doc = xml.dom.minidom.parse('test.xml') 
root = doc.getElementsByTagName('Store')[0]
output = setcheckout(root, checkout)

tmp_config = '/tmp/tmp_config.xml' 
fw = open(tmp_config, 'w')
fw.write(doc.toxml())
fw.close()

Answer 1

我不完全确定你所说的“结账”是什么意思。该脚本将找到该元素并更改该元素的值。也许您可以根据您的特定需求进行调整。

import xml.dom.minidom as DOM

# find the author as a child of the "Store"
def getAuthor(parent, author):
  # by looking at the children
  for child in [child for child  in parent.childNodes 
                if child.nodeType != DOM.Element.TEXT_NODE]:
    if child.tagName == author:
      return child
  return None

def alterElement(parent, attribute, newValue):
  found = False;
  # look through the child elements, skipping Text_Nodes 
  #(in your example these hold the "values"
  for child in [child for child  in parent.childNodes 
                if child.nodeType != DOM.Element.TEXT_NODE]:

    # if the child element tagName matches target element name
    if child.tagName == attribute:
      # alter the data, i.e. the Text_Node value, 
      # which is the firstChild of the "isbn" element
      child.firstChild.data = newValue
      return True

    else:
      # otherwise look at all the children of this node.
      found = alterElement(child, attribute, newValue)

    if found:
      break 

  # return found status
  return found

doc = DOM.parse("test.xml")
# This assumes that there is only one "Store" in the file
root = doc.getElementsByTagName("Store")[0]

# find the author
# this assumes that there are no duplicate author names in the file
author = getAuthor(root, "foo")
if not author:
  print "Author not found!"
else:
  # alter an element
  if not alterElement(author, "isbn", "987654321"):
    print "isbn not found"
  else:
    # output the xml
    tmp_config = '/tmp/tmp_config.xml'
    f = open(tmp_config, 'w')
    doc.writexml( f )
    f.close()

总体思路是，将作者的姓名与“Store”元素的子元素的 tagName 进行匹配，然后递归遍历作者的子元素，查找与目标元素 tagName 的匹配项。此解决方案中做出了很多假设，但它可能会帮助您入门。尝试在不使用递归的情况下处理像 XML 这样的分层结构是很痛苦的。

---

回想起来，“alterElement”函数中有一个错误。我已经解决了这个问题（注意“找到的”变量”）