Extracting a value from an xml file

[ironmonkey69]

Is there a way to use python to extract a value from an xml file?

[KaezarRex]

Is there a way to use python to extract a value from an xml file?

There are many different ways to parse xml in python. I would suggest looking into a module called minidom in the python library reference. They have a simple example to help you get started.

[ironmonkey69]

I can use the code below to parse the file, but how can I extract a value of a tag such as 'name' with a value and return that value to an external program?

from xml.dom.minidom import parse, parseString
dom1 = parse('c:\\temp\\mydata.xml') # parse an XML file by name
 

[ironmonkey69]

this is what the contents of the xml file looks like and I want to take the value of 'name' and return that to an external program.

<servicing name="color-measure-print-and-scan">
 

[KaezarRex]

this is what the contents of the xml file looks like and I want to take the value of 'name' and return that to an external program.

<servicing name="color-measure-print-and-scan">
 

elements = dom1.getElementsByTagName("servicing")
return elements[0].attributes['name'].value

If you have multiple servicing tags, just iterate through elements instead of only looking at the first index.

[ironmonkey69]

My python script looks like this

import xml.dom.minidom
 
from xml.dom.minidom import parse, parseString
dom1 = parse('/home/test.xml') # parse an XML file by name
elements = dom1.getElementsByTagName("servicing")
    return elements[0].attributes['name'].value
 

I get an error that says that return is outside function. I am using python 2.0.

[KaezarRex]

My python script looks like this

import xml.dom.minidom
 
from xml.dom.minidom import parse, parseString
dom1 = parse('/home/test.xml') # parse an XML file by name
elements = dom1.getElementsByTagName("servicing")
    return elements[0].attributes['name'].value
 

I get an error that says that return is outside function. I am using python 2.0.

Sorry, I misunderstood what you mean by returning the value to an external program.
Try this:

import xml.dom.minidom
from xml.dom.minidom import parse, parseString
dom1 = parse('/home/test.xml')
elements = dom1.getElementsByTagName("servicing")
name = elements[0].attributes['name'].value
print name

[ironmonkey69]

when i run this script, it says "ImportError: No module named xml.dom.minidom"
Is there any other way to perform this function without using minidom?

[KaezarRex]

when i run this script, it says "ImportError: No module named xml.dom.minidom"
Is there any other way to perform this function without using minidom?

That's strange that it won't import because minidom is automatically included in python. I am using 2.5, but I'm almost positive that the minidom module should work the same as in 2.0.
As far as other ways to parse go, I have only used minidom to extract info from xml files, so I don't know of any other way to recommend.

[bartonc]

That's strange that it won't import because minidom is automatically included in python. I am using 2.5, but I'm almost positive that the minidom module should work the same as in 2.0.
As far as other ways to parse go, I have only used minidom to extract info from xml files, so I don't know of any other way to recommend.

Yep. And 2.4.4 the docs chapter is "13.7 xml.dom.minidom".

[bartonc]

when i run this script, it says "ImportError: No module named xml.dom.minidom"
Is there any other way to perform this function without using minidom?

This also makes no sense to me because you made it past the import in your reply #6. Something has changed since then. Can you think what that might be?

[ironmonkey69]

Is there a way to parse the xml file using the xmllib?

[ghostdog74]

this is what the contents of the xml file looks like and I want to take the value of 'name' and return that to an external program.

<servicing name="color-measure-print-and-scan">
 

its only 1 line? can you show more sample of your xml file, if any?

[ironmonkey69]

sure

<servicing name="alignment">
 
    <!-- ************************************  BEGIN OF PASS  ****************************************** -->
 
    <!-- TRJ-002448 Changed to prevent the carriage from going to the secondary spittoon during printhead alignment 
        plots. This happens because the printmode is a mix of uni-directional and bi-directional print modes.  Date 11th April 2006 -->
    <begin-of-pass>
        <flying-spit type="fixed">                                                                                                                                                                          
            <parameters>
                <fixed mode="only-SVS"/>
            </parameters>
        </flying-spit>
    </begin-of-pass>
 
 
    <!-- ************************************  BEGIN OF PAGE  ****************************************** -->
 
    <!-- Disable drop detection -->
    <begin-of-page>
        <drop-detection enabled="0">
        </drop-detection>
    </begin-of-page>
 
 
    <!-- ************************************  END OF JOB  ****************************************** -->
 
    <!-- Disable drop detection -->
    <end-of-job>
        <drop-detection enabled="0">
        </drop-detection>
    </end-of-job>
 
</servicing>
 

[bvdet]

sure

<servicing name="alignment">
 
    <!-- ************************************  BEGIN OF PASS  ****************************************** -->
 
    <!-- TRJ-002448 Changed to prevent the carriage from going to the secondary spittoon during printhead alignment 
        plots. This happens because the printmode is a mix of uni-directional and bi-directional print modes.  Date 11th April 2006 -->
    <begin-of-pass>
        <flying-spit type="fixed">                                                                                                                                                                          
            <parameters>
                <fixed mode="only-SVS"/>
            </parameters>
        </flying-spit>
    </begin-of-pass>
 
 
    <!-- ************************************  BEGIN OF PAGE  ****************************************** -->
 
    <!-- Disable drop detection -->
    <begin-of-page>
        <drop-detection enabled="0">
        </drop-detection>
    </begin-of-page>
 
 
    <!-- ************************************  END OF JOB  ****************************************** -->
 
    <!-- Disable drop detection -->
    <end-of-job>
        <drop-detection enabled="0">
        </drop-detection>
    </end-of-job>
 
</servicing>
 

If all you want to do is read that one value, you might consider a regex solution:

import re
 
keyword = 'servicing'
patt = re.compile(r'<%s(.*)>' % keyword)
 
s = patt.search(open('file_name.xml').read()).group(1)
if '=' in s:
    print s.split('=')[1]

Output:
>>> "alignment"

[ghostdog74]

looks like you only have one line of "<servicing name" in your xml file. so what's stopping you for using string functions like replace, or even indexing?

for line in open("xmlfile"):
    if line.startswith("<servicing name="):
        line=line.replace("<servicing name=\"","").replace("\">","")
        print line
 

using indexing/slicing:

for line in open("xmlfile"):
    if line.startswith("<servicing name="):
        print line[len("<servicing name=\""):-2]