2

我正在尝试学习 python，同时也为自己节省了很多工作。

我有一个 xml 文件和一个字典文件，将旧设备 ID 映射到新设备 ID。

我正在尝试遍历树，并且对于与字典键匹配的任何logical_devid 子项，或者为每个字典键找到相应的logical_devid。在任何一种情况下，将logical_devid.text 替换为新值。

例如 xml 片段

<lun>
   <pseudo_dev>emcpower146a</pseudo_dev>
   <udev>0x12b00000490</udev>
   <product_id>symmetrix</product_id>
   <frame_id>000192604705</frame_id>
   <logical_devid_type>symm_id</logical_devid_type>
   <logical_devid>0A43</logical_devid>
 </lun>

的文本文件 

0A40   0127
0A41   0128
0A42   0129
0A43   012A

我已将 xml 文件加载为 ElementTree 对象，并将文本文件加载到字典中。 

import xml.etree.cElementTree as ET
tree = ET.ElementTree(file='emcpower.mappings')
d = {}
with open("translate-table.txt") as f: 
    for line in f: 
        (old, new) = line.split() 
        d[(old)] = new

我一直试图找出迭代和替换 elem.text 的最佳方法，我认为最好的方法是迭代字典中的已知更改。

for old_devid, new_devid in d.iteritems():

然后为与 old_devid 匹配的子logical_devid 执行某种 xml 查找，将 elem.text 设置为 new_devid

这是我想要的完整脚本：
#!/usr/bin/python

try:
        import xml.etree.cElementTree as ET
except ImportError:
        import xml.etree.ElementTree as ET

#read in emcpower.mappings file as an entire xml tree of elements
tree = ET.ElementTree(file='emcpower.mappings')

# this defines a dictionary with the contents of the translate table which
# is simply the old device ID as key and new device id as value

d = {}
with open("translate-table.txt") as f:
        for line in f:
                (old, new) = line.split()
                d[(old)] = new

for elem in tree.iterfind('lun/logical_devid'):
        old_devid = elem.text
        new_devid = d.get(old_devid)
        try:
                new_devid
        except NameError:
                new_devid = None
        else:
                if new_devid:
                        elem.text = new_devid
                        print "The logical_devid will be changed to", elem.text



tree.write('emcpower.mappings.new', )
4

1 回答 1

0

我认为遍历tree并查看每个logical_devid是否在d. 一旦你有logical_devid一个变量（比如，old_devid），然后：

new_devid = d.get(old_devid)

会看看你是否有替代品。如果new_devid is null那么它不在字典中。否则，应该替换树中new_devid的当前值。logical_devid

于 2013-06-16T02:25:08.033 回答