How to pretty print nested dictionaries?

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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?

27 Answers

By this way you can print it in pretty way for example your dictionary name is yasin

import json

print (json.dumps(yasin, indent=2))

or, safer:

print (json.dumps(yasin, indent=2, default=str))

One of the most pythonic ways for that is to use the already build pprint module.

The argument that you need for define the print depth is as you may expect depth

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

That's it !

I had to pass the default parameter as well, like this:

print(json.dumps(my_dictionary, indent=4, default=str))

and if you want the keys sorted, then you can do:

print(json.dumps(my_dictionary, sort_keys=True, indent=4, default=str))

in order to fix this type error:

TypeError: Object of type 'datetime' is not JSON serializable

which caused by datetimes being some values in the dictionary.

The modern solution here is to use rich. Install with

pip install rich

and use as

from rich import print

d = {
    "Alabama": "Montgomery",
    "Alaska": "Juneau",
    "Arizona": "Phoenix",
    "Arkansas": "Little Rock",
    "California": "Sacramento",
    "Colorado": "Denver",
    "Connecticut": "Hartford",
    "Delaware": "Dover",
    "Florida": "Tallahassee",
    "Georgia": "Atlanta",
    "Hawaii": "Honolulu",
    "Idaho": "Boise",
}
print(d)

The output is nicely indented:

enter image description here

Another option with yapf:

from pprint import pformat
from yapf.yapflib.yapf_api import FormatCode

dict_example = {'1': '1', '2': '2', '3': [1, 2, 3, 4, 5], '4': {'1': '1', '2': '2', '3': [1, 2, 3, 4, 5]}}
dict_string = pformat(dict_example)
formatted_code, _ = FormatCode(dict_string)

print(formatted_code)

Output:

{
    '1': '1',
    '2': '2',
    '3': [1, 2, 3, 4, 5],
    '4': {
        '1': '1',
        '2': '2',
        '3': [1, 2, 3, 4, 5]
    }
}

You can use print-dict

from print_dict import pd

dict1 = {
    'key': 'value'
} 

pd(dict1)

Output:

{
    'key': 'value'
}

Output of this Python code:

{
    'one': 'value-one',
    'two': 'value-two',
    'three': 'value-three',
    'four': {
        '1': '1',
        '2': '2',
        '3': [1, 2, 3, 4, 5],
        '4': {
            'method': <function custom_method at 0x7ff6ecd03e18>,
            'tuple': (1, 2),
            'unicode': '✓',
            'ten': 'value-ten',
            'eleven': 'value-eleven',
            '3': [1, 2, 3, 4]
        }
    },
    'object1': <__main__.Object1 object at 0x7ff6ecc588d0>,
    'object2': <Object2 info>,
    'class': <class '__main__.Object1'>
}

Install:

$ pip install print-dict

Disclosure: I'm the author of print-dict

pout can pretty print anything you throw at it, for example (borrowing data from another answer):

data = {'a':2, 'b':{'x':3, 'y':{'t1': 4, 't2':5}}}
pout.vs(data)

would result in output printed to the screen like:

{
    'a': 2,
    'b':
    {
        'y':
        {
            't2': 5,
            't1': 4
        },
        'x': 3
    }
}

or you can return the formatted string output of your object:

v = pout.s(data)

Its primary use case is for debugging so it doesn't choke on object instances or anything and it handles unicode output as you would expect, works in python 2.7 and 3.

disclosure: I'm the author and maintainer of pout.

I used what you guys taught me plus the power of decorators to overload the classic print function. Just change the indent to your needs. I added it as a gist in github in case you want to star(save) it.

def print_decorator(func):
    """
    Overload Print function to pretty print Dictionaries 
    """
    def wrapped_func(*args,**kwargs):
        if isinstance(*args, dict):
            return func(json.dumps(*args, sort_keys=True, indent=2, default=str))
        else:
            return func(*args,**kwargs)
    return wrapped_func
print = print_decorator(print)

Now just use print as usual.

I tried the following and got my desired results

Method 1: Step 1: Install print_dict by typing the following command in cmd

pip install print_dict

Step 2: Import print_dict as

from print_dict import pd

Step 3: Printing using pd

pd(your_dictionary_name)

Example Output:

{
    'Name': 'Arham Rumi',
    'Age': 21,
    'Movies': ['adas', 'adfas', 'fgfg', 'gfgf', 'vbxbv'],
    'Songs': ['sdfsd', 'dfdgfddf', 'dsdfd', 'sddfsd', 'sdfdsdf']
}

Method 2: We can also use for loop to print the dictionary using items method

for key, Value in your_dictionary_name.items():
    print(f"{key} : {Value}")

The easiest is to install IPython and use something like below

from IPython.lib.pretty import pretty


class MyClass:
    __repr__(self):
       return pretty(data)  # replace data with what makes sense

In your case

print(pretty(mydict))

prettyformatter

Disclaimer: I'm the author of the package.

For a comparison with other formatters, see Other Formatters.


Formatting

Unlike pprint.pprint, prettyformatter spreads vertically more and attempts to align items more.

Unlike json.dumps, prettyformatter is usually more compact and attempts to align dictionary values wherever reasonable.

from prettyformatter import pprint

batters = [
    {"id": "1001", "type": "Regular"},
    {"id": "1002", "type": "Chocolate"},
    {"id": "1003", "type": "Blueberry"},
    {"id": "1004", "type": "Devil's Food"},
]

toppings = [
    {"id": "5001", "type": None},
    {"id": "5002", "type": "Glazed"},
    {"id": "5005", "type": "Sugar"},
    {"id": "5007", "type": "Powdered Sugar"},
    {"id": "5006", "type": "Chocolate with Sprinkles"},
    {"id": "5003", "type": "Chocolate"},
    {"id": "5004", "type": "Maple"},
]

data = {"id": "0001", "type": "donut", "name": "Cake", "ppu": 0.55, "batters": batters, "topping": toppings}

pprint(data)

Output:

{
    "id"    : "0001",
    "type"  : "donut",
    "name"  : "Cake",
    "ppu"   : 0.55,
    "batters":
        [
            {"id": "1001", "type": "Regular"},
            {"id": "1002", "type": "Chocolate"},
            {"id": "1003", "type": "Blueberry"},
            {"id": "1004", "type": "Devil's Food"},
        ],
    "topping":
        [
            {"id": "5001", "type": None},
            {"id": "5002", "type": "Glazed"},
            {"id": "5005", "type": "Sugar"},
            {"id": "5007", "type": "Powdered Sugar"},
            {"id": "5006", "type": "Chocolate with Sprinkles"},
            {"id": "5003", "type": "Chocolate"},
            {"id": "5004", "type": "Maple"},
        ],
}

Features

See here for the full documentation.

JSON

Unlike pprint.pprint, prettyformatter supports JSON conversion via the json=True argument. This includes changing None to null, True to true, False to false, and correct use of quotes.

Unlike json.dumps, prettyformatter supports JSON coercion with more data types. This includes changing any dataclass or mapping into a dict and any iterable into a list.

from dataclasses import dataclass

from prettyformatter import PrettyDataclass, pprint


@dataclass(unsafe_hash=True)
class Point(PrettyDataclass):
    x: int
    y: int


pprint((Point(1, 2), Point(3, 4)), json=True)

Output:

[{"x": 1, "y": 2}, {"x": 3, "y": 4}]

Customization

Unlike pprint.pprint or json.dumps, prettyformatter supports easy customization with additional types.

Implementing the __pargs__ and/or __pkwargs__ methods for a prettyformatter.PrettyClass subclass allows one to easily customize classes in the form of "cls_name(*args, **kwargs)".

from prettyformatter import PrettyClass


class Dog(PrettyClass):

    def __init__(self, name, **kwargs):
        self.name = name

    def __pkwargs__(self):
        return {"name": self.name}


print(Dog("Fido"))
"""
Dog(name="Fido")
"""

print(Dog("Fido"), json=True)
"""
{"name": "Fido"}
"""

Implementing the __pformat__ method allows even more specific implementations of the pformat function.

Implementing the @prettyformatter.register function also allows customizing classes that already exist in the same way implementing __pformat__ would.

import numpy as np
from prettyformatter import pprint, register

@register(np.ndarray)
def pformat_ndarray(obj, specifier, depth, indent, shorten, json):
    if json:
        return pformat(obj.tolist(), specifier, depth, indent, shorten, json)
    with np.printoptions(formatter=dict(all=lambda x: format(x, specifier))):
        return repr(obj).replace("\n", "\n" + " " * depth)

pprint(dict.fromkeys("ABC", np.arange(9).reshape(3, 3)))

Output:

{
    "A":
        array([[0, 1, 2],
               [3, 4, 5],
               [6, 7, 8]]),
    "B":
        array([[0, 1, 2],
               [3, 4, 5],
               [6, 7, 8]]),
    "C":
        array([[0, 1, 2],
               [3, 4, 5],
               [6, 7, 8]]),
}

Use this function:

def pretty_dict(d, n=1):
    for k in d:
        print(" "*n + k)
        try:
            pretty_dict(d[k], n=n+4)
        except TypeError:
            continue

Call it like this:

pretty_dict(mydict)

This is what I came up with while working on a class that needed to write a dictionary in a .txt file:

@staticmethod
def _pretty_write_dict(dictionary):

    def _nested(obj, level=1):
        indentation_values = "\t" * level
        indentation_braces = "\t" * (level - 1)
        if isinstance(obj, dict):
            return "{\n%(body)s%(indent_braces)s}" % {
                "body": "".join("%(indent_values)s\'%(key)s\': %(value)s,\n" % {
                    "key": str(key),
                    "value": _nested(value, level + 1),
                    "indent_values": indentation_values
                } for key, value in obj.items()),
                "indent_braces": indentation_braces
            }
        if isinstance(obj, list):
            return "[\n%(body)s\n%(indent_braces)s]" % {
                "body": "".join("%(indent_values)s%(value)s,\n" % {
                    "value": _nested(value, level + 1),
                    "indent_values": indentation_values
                } for value in obj),
                "indent_braces": indentation_braces
            }
        else:
            return "\'%(value)s\'" % {"value": str(obj)}

    dict_text = _nested(dictionary)
    return dict_text

Now, if we have a dictionary like this:

some_dict = {'default': {'ENGINE': [1, 2, 3, {'some_key': {'some_other_key': 'some_value'}}], 'NAME': 'some_db_name', 'PORT': '', 'HOST': 'localhost', 'USER': 'some_user_name', 'PASSWORD': 'some_password', 'OPTIONS': {'init_command': 'SET foreign_key_checks = 0;'}}}

And we do:

print(_pretty_write_dict(some_dict))

We get:

{
    'default': {
        'ENGINE': [
            '1',
            '2',
            '3',
            {
                'some_key': {
                    'some_other_key': 'some_value',
                },
            },
        ],
        'NAME': 'some_db_name',
        'OPTIONS': {
            'init_command': 'SET foreign_key_checks = 0;',
        },
        'HOST': 'localhost',
        'USER': 'some_user_name',
        'PASSWORD': 'some_password',
        'PORT': '',
    },
}
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