xmltodict unparse解析不一样

Question

import xmltodict

test_data = {'value1': 1, 'parent_lvl1': {'parent_Lvl2': {'value1': 2, 'value2': 3}}}
print("test_data : ", test_data)

xml_str = xmltodict.unparse({'settings' : test_data})
print("dict to xml string :", xml_str)

test_data_re = xmltodict.parse(xml_str, dict_constructor=dict)
print("xml_str back to dict : ", test_data_re['settings'])

Results are : test_data : {'parent_lvl1': {'parent_Lvl2': {'value2': 3, 'value1': 2}}, 'value1': 1} dict to xml string : 321 xml_str back to dict : {'parent_lvl1': {'parent_Lvl2': {'value2': '3', 'value1': '2'}}, 'value1': '1'}

The result is that when I do a comparison between the old dict and the new they are different. How do I get xmltodict to unparse what it parsed in the first place

Answer 1

I don't think you should expect both of them be the same in general and all the time.

The integer values are not being cast to integers during parsing automatically and everything is parsed into strings, but you have a few ways to control the type conversion. For example, you could specify a post processor and try converting values to integers for keys starting with value :

def postprocessor(path, key, value):
    if key.startswith("value"):
        try:
            return key, int(value)
        except (ValueError, TypeError):
            return key, value
    return key, value


test_data_re = xmltodict.parse(xml_str, dict_constructor=dict, postprocessor=postprocessor)
print("xml_str back to dict : ", test_data_re['settings'])

This would produce:

xml_str back to dict :  {'value1': 1, 'parent_lvl1': {'parent_Lvl2': {'value1': 2, 'value2': 3}}}

Btw, a good place to look for xmltodict sample usages is xmltodict tests , check it out.