Python human readable object serialization

For simple cases pprint() and eval() come to mind.

Using your example:

>>> d = {'age': 27,
...  'name': 'Joe',
...  'numbers': [1, 
...              2, 
...              3,
...              4,
...              5],
...  'subdict': {
...              'first': 1, 
...              'second': 2,
...               'third': 3
...              }
... }
>>> 
>>> from pprint import pprint
>>> pprint(d)
{'age': 27,
 'name': 'Joe',
 'numbers': [1, 2, 3, 4, 5],
 'subdict': {'first': 1, 'second': 2, 'third': 3}}
>>> 

I would think twice about fixing two requirements with the same tool. Have you considered using pickle for the serializing and then pprint() (or a more fancy object viewer) for humans looking at the objects?

If its just Python list, dictionary and tuple object. - JSON is the way to go. Its human readable, very easy to handle and language independent too.

Caution: Tuples will be converted to lists in simplejson.

In [109]: simplejson.loads(simplejson.dumps({'d':(12,3,4,4,5)}))
Out[109]: {u'd': [12, 3, 4, 4, 5]}

You should check out jsonpickle (https://github.com/jsonpickle/jsonpickle). It will write out any python object into a json file. You can then read that file back into a python object. The nice thing is the inbetween file is very readable because it's json.