Any way to properly pretty-print ordered dictionaries?

Question

I like the pprint module in Python. I use it a lot for testing and debugging. I frequently use the width option to make sure the output fits nicely within my terminal window

Answer 1

The pprint() method is just invoking the __repr__() method of things in it, and OrderedDict doesn't appear to do much in it's method (or doesn't have one or something).

Here's a cheap solution that should work IF YOU DON'T CARE ABOUT THE ORDER BEING VISIBLE IN THE PPRINT OUTPUT, which may be a big if:

class PrintableOrderedDict(OrderedDict):
    def __repr__(self):
        return dict.__repr__(self)

I'm actually surprised that the order isn't preserved... ah well.

Answer 2

As of Python 3.8 : pprint.PrettyPrinter exposes the sort_dicts keyword parameter.

True by default, setting it to False will leave the dictionary unsorted.

>>> from pprint import PrettyPrinter

>>> x = {'John': 1,
>>>      'Mary': 2,
>>>      'Paul': 3,
>>>      'Lisa': 4,
>>>      }

>>> PrettyPrinter(sort_dicts=False).pprint(x)

Will output :

{'John': 1, 
 'Mary': 2, 
 'Paul': 3,
 'Lisa': 4}

Reference : https://docs.python.org/3/library/pprint.html

Answer 3

The following will work if the order of your OrderedDict is an alpha sort, since pprint will sort a dict before print.

pprint(dict(o.items()))