In Python, is there an easy way to edit xml in place?

Suppose I want to edit a node in xml and edit one of its attributes. I want to be able to do a simple file diff to just see one row changed. Dumping the xml using prettyprint change开发者_StackOverflows the whole xml structure.

Well then don't use prettyprint.

In xml.dom.minidom for example, if you do

doc = xml.dom.minidom.parse(inputfile)
do_something_with(doc)
outputfile.write(doc.toxml("utf-8").decode("utf-8"))

all the structure/whitespace etc. will remain unchanged.

Consider NOT using "a simple file diff". See this SO question.