我正在使用 lxml
库读取 xml 模板,插入/更改一些元素,并保存生成的 xml。我使用 etree.Element
和 etree.SubElement
方法即时创建的元素之一:
tree = etree.parse(r'xml_archive\templates\metadata_template_pts.xml')
root = tree.getroot()
stream = []
for element in root.iter():
if isinstance(element.tag, basestring):
stream.append(element.tag)
# Find "keywords" element and insert a new "theme" element
if element.tag == 'keywords' and 'theme' not in stream:
theme = etree.Element('theme')
themekt = etree.SubElement(theme, 'themekt').text = 'None'
for tk in themekeys:
themekey = etree.SubElement(theme, 'themekey').text = tk
element.insert(0, theme)
很好地打印到屏幕print etree.tostring(theme, pretty_print=True)
:
<theme>
<themekt>None</themekt>
<themekey>Hydrogeology</themekey>
<themekey>Stratigraphy</themekey>
<themekey>Floridan aquifer system</themekey>
<themekey>Geology</themekey>
<themekey>Regional Groundwater Availability Study</themekey>
<themekey>USGS</themekey>
<themekey>United States Geological Survey</themekey>
<themekey>thickness</themekey>
<themekey>altitude</themekey>
<themekey>extent</themekey>
<themekey>regions</themekey>
<themekey>upper confining unit</themekey>
<themekey>FAS</themekey>
<themekey>base</themekey>
<themekey>geologic units</themekey>
<themekey>geology</themekey>
<themekey>extent</themekey>
<themekey>inlandWaters</themekey>
</theme>
但是,当使用 etree.ElementTree(root).write(out_xml_file, method='xml', pretty_print=True)
写出 xml 时,此元素在输出文件中被展平:
<theme><themekt>None</themekt><themekey>Hydrogeology</themekey><themekey>Stratigraphy</themekey><themekey>Floridan aquifer system</themekey><themekey>Geology</themekey><themekey>Regional Groundwater Availability Study</themekey><themekey>USGS</themekey><themekey>United States Geological Survey</themekey><themekey>thickness</themekey><themekey>altitude</themekey><themekey>extent</themekey><themekey>regions</themekey><themekey>upper confining unit</themekey><themekey>FAS</themekey><themekey>base</themekey><themekey>geologic units</themekey><themekey>geology</themekey><themekey>extent</themekey><themekey>inlandWaters</themekey></theme>
文件的其余部分写得很好,但是这个特定元素造成了(纯粹是美学上的)麻烦。对我做错了什么有什么想法吗?
下面是模板 xml 文件中的一段标记(将其另存为“template.xml”以使用底部的代码片段运行)。仅当我解析现有文件并插入新元素时才会出现标签展平,而不是在使用 lxml
从头创建 xml 时。
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="fgdc_classic.xsl"?>
<metadata xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://water.usgs.gov/GIS/metadata/usgswrd/fgdc-std-001-1998.xsd">
<keywords>
<theme>
<themekt>ISO 19115 Topic Categories</themekt>
<themekey>environment</themekey>
<themekey>geoscientificInformation</themekey>
<themekey>inlandWaters</themekey>
</theme>
<place>
<placekt>None</placekt>
<placekey>Florida</placekey>
<placekey>Georgia</placekey>
<placekey>Alabama</placekey>
<placekey>South Carolina</placekey>
</place>
</keywords>
</metadata>
下面是与标记片段(上方)一起使用的代码片段:
# Create new theme element to insert into root
themekeys = ['Hydrogeology', 'Stratigraphy', 'inlandWaters']
tree = etree.parse(r'template.xml')
root = tree.getroot()
stream = []
for element in root.iter():
if isinstance(element.tag, basestring):
stream.append(element.tag)
# Edit theme keywords
if element.tag == 'keywords':
theme = etree.Element('theme')
themekt = etree.SubElement(theme, 'themekt').text = 'None'
for tk in themekeys:
themekey = etree.SubElement(theme, 'themekey').text = tk
element.insert(0, theme)
# Write XML to new file
out_xml_file = 'test.xml'
etree.ElementTree(root).write(out_xml_file, method='xml', pretty_print=True)
with open(out_xml_file, 'r') as f:
lines = f.readlines()
with open(out_xml_file, 'w') as f:
f.write('<?xml version="1.0" encoding="UTF-8"?>\n')
for line in lines:
f.write(line)
最佳答案
如果你替换这一行:
tree = etree.parse(r'template.xml')
这些行:
parser = etree.XMLParser(remove_blank_text=True)
tree = etree.parse(r'template.xml', parser)
然后它将按预期工作。诀窍是使用 XMLParser remove_blank_text
选项设置为 True
。任何现有的可忽略空格都将被删除,因此不会破坏后续的 pretty-print 。
关于python - 即使在 pretty_print=True 时,使用 lxml 编写也不会发出空格,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/31274414/