Replacing XML element in Python

Question

I am trying to replace the element inside of bbox with a new set of coordinates.

my code :

    # import element tree
    import xml.etree.ElementTree as ET 


    #import xml file
    tree = ET.parse('C:/highway.xml')
    root = tree.getroot()

    #replace bounding box with new coordinates

    elem = tree.findall('bbox')
    elem.txt = '40.5,41.5,-12.0,-1.2'

my xml file:

   <geoEtl>
    <source>
        <server>localhost</server>
        <port>xxxx</port>
        <db>vxxx</db>
        <user>xxxx</user>
        <passwd>xxxx</passwd>
    </source>
    <targetDir>/home/firstuser/</targetDir>
    <bbox>-52.50,-1.9,52.45,-1.85</bbox>
    <extractions>
        <extraction>
            <table>geo_db_roads</table>
            <outputName>highways</outputName>
            <filter>highway = 'motorway'</filter>
            <geometry>way</geometry>
            <fields>
                <field>name</field>             
            </fields>
        </extraction>
    </extractions>
   </geoEtl>

have tried a variety of ways to do of things i found here but it doesnt seem to be working. thanks.

The error I'm receiving is as follows:

line 20, in <module> elem.txt = '40.5,41.5,-12.0,-1.2' AttributeError: 'list' object has no attribute 'txt' –

line 20, in elem.txt = '40.5,41.5,-12.0,-1.2' AttributeError: 'list' object has no attribute 'txt' — Moggy, Jul 02 '13 at 22:55

score 9 · Accepted Answer · answered Jul 02 '13 at 22:55

9

The findall function, as the name implies, finds all matching elements, not just one.

So, after this:

elem = tree.findall('bbox')

elem is a list of Elements. And, as with any other list, this:

elem.txt = '40.5,41.5,-12.0,-1.2'

Is going to give you an error:

AttributeError: 'list' object has no attribute 'txt'

If you want to do something to every member of a list, you have to loop over it:

elems = tree.findall('bbox')
for elem in elems:
    elem.txt = '40.5,41.5,-12.0,-1.2'

answered Jul 02 '13 at 22:55

abarnert

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ok awesome it runs no problem now, should be it rewriting the new coordinates on my XML file or is that a different issue? – Moggy Jul 02 '13 at 23:01
2

@Moggy: `ET.parse('C:/highway.xml')` just parses the file into a tree in memory. If you want to modify the XML file, you have to edit the tree, then _save it back to a file_`. You can do `tree.write('C:/highway.xml')` if you want to overwrite the original version with the new one. – abarnert Jul 02 '13 at 23:23

score 3 · Answer 2 · answered Jul 02 '13 at 23:15

3

If your file isn't update it is most likely because you are not saving it, you can use the tree.write method to do just that.

tree.write('output.xml')

answered Jul 02 '13 at 23:15

John

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score 1 · Answer 3 · answered Dec 12 '16 at 14:25

# import element tree
import xml.etree.ElementTree as ET 

#import xml file
tree = ET.parse('C:/highway.xml')
root = tree.getroot()

elems = root.findall(".//bbox")

for elem in elems:
    elem.text = '40.5,41.5,-12.0,-1.2'

tree.write('C:/highway.xml')

score 0 · Answer 4 · answered Jul 02 '13 at 22:56

0

If you want to replace the text of all boundingboxes with '40.5,41.5,-12.0,-1.2', try this

bboxes = tree.xpath('//bbox')
for bbox in bboxes:
    bbox.text= '40.5,41.5,-12.0,-1.2'

answered Jul 02 '13 at 22:56

kamjagin

3,614
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2

i get AttributeError: 'ElementTree' object has no attribute 'xpath' – Moggy Jul 02 '13 at 23:06
Yes - sorry. I also had slightly simpler code for parsing - I used etree as my base class and etree includes the xpath function. I had assumed that ElementTree has that too but I never double-checked it – kamjagin Jul 03 '13 at 11:12
@kamjagin: There is no class called `etree` anywhere. In both the 2.x and 3.x stdlibs, `etree` is a package with nothing in it but the `ElementTree` module; in the separately-installable module from Fredrick Lundh's website, nothing at all has that name; in `lxml`, `etree` is a module with roughly the same API as `ElementTree` in the others. `Element` handles XPath syntax in the `findall` method; in the `lxml` implementation you can also call it as `xpath`, but you still call it on `Element`s, not an empty package that you've somehow used as a base class. – abarnert Jul 03 '13 at 17:23

Replacing XML element in Python

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