How to pretty print nested dictionaries?

How can I pretty print a dictionary with depth of ~4 in Python? I tried pretty printing with pprint(), but it did not work:

import pprint 
pp = pprint.PrettyPrinter(indent=4)
pp.pprint(mydict)

I simply want an indentation ("\t") for each nesting, so that I get something like this:

key1
    value1
    value2
    key2
       value1
       value2

etc.

How can I do this?

Solution 1:

My first thought was that the JSON serializer is probably pretty good at nested dictionaries, so I'd cheat and use that:

>>> import json
>>> print(json.dumps({'a':2, 'b':{'x':3, 'y':{'t1': 4, 't2':5}}},
...                  sort_keys=True, indent=4))
{
    "a": 2,
    "b": {
        "x": 3,
        "y": {
            "t1": 4,
            "t2": 5
        }
    }
}

Solution 2:

I'm not sure how exactly you want the formatting to look like, but you could start with a function like this:

def pretty(d, indent=0):
   for key, value in d.items():
      print('\t' * indent + str(key))
      if isinstance(value, dict):
         pretty(value, indent+1)
      else:
         print('\t' * (indent+1) + str(value))

Solution 3:

You could try YAML via PyYAML. Its output can be fine-tuned. I'd suggest starting with the following:

print yaml.dump(data, allow_unicode=True, default_flow_style=False)

The result is very readable; it can be also parsed back to Python if needed.

Edit:

Example:

>>> import yaml
>>> data = {'a':2, 'b':{'x':3, 'y':{'t1': 4, 't2':5}}}
>>> print yaml.dump(data, default_flow_style=False)
a: 2
b:
  x: 3
  y:
    t1: 4
    t2: 5