Python and default dict, how to pprint

Question

I am using default dict. I need to pprint.

However, when I pprint ...this is how it looks.

defaultdict(<functools.partial object at 0x1f68418>, {u'300:250': defaultdict(<functools.partial object at 0x1f683c0>, {0: defaultdict(<type 'list'>, {u'agid1430864021': {u'status': u'0', u'exclude_regi..........

How to I get pprint to work with default dict?

score 45 · Accepted Answer · answered Oct 16 '12 at 23:38

45

I've used pprint(dict(defaultdict)) before as a work-around.

answered Oct 16 '12 at 23:38

Jon Clements

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22

I've found this solution does not give the desired effect if the object is a nested hierarchy of deafultdict objects. – krd Mar 14 '14 at 21:02
5

For nested defaultdicts: `pprint({k: dict(v) for k, v in dict(group_ids).items()})` – Nov 14 '15 at 18:00

score 25 · Answer 2 · answered Aug 22 '13 at 09:29

25

The best solution I've found is a bit of a hack, but an elegant one (if a hack can ever be):

class PrettyDefaultDict(collections.defaultdict):
    __repr__ = dict.__repr__

And then use the PrettyDefaultDict class instead of collections.defaultdict. It works because of the way the pprint module works (at least on 2.7):

r = getattr(typ, "__repr__", None)
if issubclass(typ, dict) and r is dict.__repr__:
    # follows pprint dict formatting

This way we "trick" pprint into thinking that our dictionary class is just like a normal dict.

answered Aug 22 '13 at 09:29

RedGlow

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@rossoft did you actually test that bit of advice (`defaultdict.__repr__ = dict.__repr__`) before telling us we can do that? – Russia Must Remove Putin Aug 08 '14 at 00:25
@Aaron Hall: it worked for me on Python 2.7. If you had a problem, tell us what it was. – mhsmith Apr 10 '15 at 18:32
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@mhsmith My question is addressed to rossoft, who must have deleted his message. But RedGlow's code could use a demo. – Russia Must Remove Putin Apr 10 '15 at 18:57
1

Ah yes, I obviously wouldn't recommend monkey-patching defaultdict itself. – mhsmith Apr 10 '15 at 19:39

score 18 · Answer 3 · answered Jan 19 '16 at 18:06

18

If you don't have to use pprint, you can use json to pretty-print the defaultdict:

print(json.dumps(my_default_dict, indent=4))

This also works for nested defaultdicts.

answered Jan 19 '16 at 18:06

Markus

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if your keys are not strings this will mess up your print – Mugen Jan 10 '19 at 09:58

score 5 · Answer 4 · edited May 23 '17 at 12:03

5

I really like this solution for dealing with nested defaultdicts. It's a bit of a hack, but does the job neatly when pdbing:

import json
data_as_dict = json.loads(json.dumps(data_as_defaultdict))
print(data_as_dict)

From: https://stackoverflow.com/a/32303615/4526633

edited May 23 '17 at 12:03

Community

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answered Jan 02 '16 at 03:26

jarekwg

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score 4 · Answer 5 · answered Oct 17 '12 at 00:04

In the same vein as Jon Clements' answer, if this is a common operation for you, you might consider subclassing defaultdict to override its repr method, as shown below.

Input:

from collections import defaultdict

class prettyDict(defaultdict):
    def __init__(self, *args, **kwargs):
        defaultdict.__init__(self,*args,**kwargs)

    def __repr__(self):
        return str(dict(self))

foo = prettyDict(list)

foo['bar'].append([1,2,3])
foo['foobar'].append([4,5,6,7,8])

print(foo)

Output:

{'foobar': [[4, 5, 6, 7, 8]], 'bar': [[1, 2, 3]]}

Python and default dict, how to pprint

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