Alex Alex - 4 months ago 21
Python Question

How to ConfigParse a file keeping multiple values for identical keys?

I need to be able to use the

ConfigParser
to read multiple values for the same key. Example config file:

[test]
foo = value1
foo = value2
xxx = yyy


With the 'standard' use of
ConfigParser
there will be one key
foo
with the value
value2
. But I need the parser to read in both values.

Following an entry on duplicate key I have created the following example code:

from collections import OrderedDict
from ConfigParser import RawConfigParser

class OrderedMultisetDict(OrderedDict):
def __setitem__(self, key, value):

try:
item = self.__getitem__(key)
except KeyError:
super(OrderedMultisetDict, self).__setitem__(key, value)
return

print "item: ", item, value
if isinstance(value, list):
item.extend(value)
else:
item.append(value)
super(OrderedMultisetDict, self).__setitem__(key, item)


config = RawConfigParser(dict_type = OrderedDict)
config.read(["test.cfg"])
print config.get("test", "foo")
print config.get("test", "xxx")

config2 = RawConfigParser(dict_type = OrderedMultisetDict)
config2.read(["test.cfg"])
print config2.get("test", "foo")
print config.get("test", "xxx")


The first part (with
config
) reads in the config file us 'usual', leaving only
value2
as the value for
foo
(overwriting/deleting the other value) and I get the following, expected output:

value2
yyy


The second part (
config2
) uses my approach to append multiple values to a list, but the output instead is

['value1', 'value2', 'value1\nvalue2']
['yyy', 'yyy']


How do I get rid of the repetitive values? I am expecting an output as follows:

['value1', 'value2']
yyy


or

['value1', 'value2']
['yyy']


(I don't mind if EVERY value is in a list...). Any suggestions welcome.

Answer

After a small modification, I was able to achieve what you want:

class MultiOrderedDict(OrderedDict):
    def __setitem__(self, key, value):
        if isinstance(value, list) and key in self:
            self[key].extend(value)
        else:
            super(OrderedDict, self).__setitem__(key, value)

config = ConfigParser.RawConfigParser(dict_type=MultiOrderedDict)
config.read(['a.txt'])
print config.get("test",  "foo")
print config.get("test",  "xxx")

Outputs:

['value1', 'value2']
['yyy']