Question

I am looking for a solution to put the content of 2 variables into a dictionary. One variable should serve as the key, the other as the value.

Here’s my code:

dom = parseString(data)
macro=dom.getElementsByTagName('macro')
for node in macro:
    d={}
    id_name=node.getElementsByTagName('id')[0].toxml()
    id_data=id_name.replace('<id>','').replace('</id>','')
    print (id_data)
    cl_name=node.getElementsByTagName('cl2')[0].toxml()
    cl_data=cl_name.replace('<cl2>','').replace('</cl2>','')
    print (cl_data)

I would like to have a dictionary with id_data as the keys, and cl_data as the values without overwriting the old data when appending. How do I go on about this?

Thanks in advance for any help!

Answer 1

from collections import defaultdict

d=defaultdict(list)

dom = parseString(data)
macro=dom.getElementsByTagName('macro')
for node in macro:
    id_name=node.getElementsByTagName('id')[0].toxml()
    id_data=id_name.replace('<id>','').replace('</id>','')
    print (id_data)
    cl_name=node.getElementsByTagName('cl2')[0].toxml()
    cl_data=cl_name.replace('<cl2>','').replace('</cl2>','')
    print (cl_data)
    d[id_data].append(cl_data)

The keys of d are the various id_datas, and the elements are lists with elements corresponding to each id_data found, in order. Of course, if you can be sure that all the id_datas are unique, you can use a regular dictionay:

d={}
for node in macro:
    ...
    d[id_data]=cl_data

This differs from your original code in that I pulled the dictionary constructor out of the loop (You don’t want to replace your dictionary each time in the loop) and actually I actually insert the elements into the dict although I’m guessing you did that too, you just don’t show it.