pprint dictionary on multiple lines

Question

I'm trying to get a pretty print of a dictionary, but I'm having no luck:

>>> import pprint
>>> a = {'first': 123, 'second': 456, 'third': {1:1, 2:2}}
>>> pprint.pprint(a)
{'first': 123, 'second': 456, 'third': {1: 1, 2: 2}}

I wanted the output to be on multiple lines, something like this:

{'first': 123,
 'second': 456,
 'third': {1: 1,
           2: 2}
}

Can pprint do this? If not, then which module does it? I'm using Python 2.7.3.

Does this answer your question? [How to pretty print nested dictionaries?](https://stackoverflow.com/questions/3229419/how-to-pretty-print-nested-dictionaries) — Georgy, May 27 '20 at 11:14
@Georgy not quite. The desired output in that question is not the same as mine is here — mulllhausen, May 29 '20 at 04:18

score 120 · Accepted Answer · answered Nov 24 '13 at 05:23

120

Use width=1 or width=-1:

In [33]: pprint.pprint(a, width=1)
{'first': 123,
 'second': 456,
 'third': {1: 1,
           2: 2}}

answered Nov 24 '13 at 05:23

Warren Weckesser

110,654
19
194
214

1

What do negative widths do? – Tim Nov 24 '13 at 05:26
1

@Tim: I just tried it, and it worked, but I don't know if that is documented somewhere. – Warren Weckesser Nov 24 '13 at 05:29
2

Negative widths don't do anything special. As the code goes along, it checks to see if the length of the partial output string is `< width`. Any negative width just means the answer will always be "no". A width of 0 will almost always (or maybe always - I don't care enough to think about perverse cases ;-)) do the same. – Tim Peters Nov 24 '13 at 06:04
1

@TimPeters: Yeah, I took a look at the source. There is a check for width==0 (it raises an error), but it seems that 0 could be treated the same as a negative value--always answer "no", as you put it--with no harm. – Warren Weckesser Nov 24 '13 at 06:26

score 54 · Answer 2 · edited Nov 04 '21 at 18:25

54

You could convert the dict to json through json.dumps(d, indent=4)

import json

print(json.dumps(item, indent=4))
{
    "second": 456,
    "third": {
        "1": 1,
        "2": 2
    },
    "first": 123
}

edited Nov 04 '21 at 18:25

binaryfunt

6,401
5
37
59

answered Oct 30 '17 at 02:37

Ryan Chou

1,086
11
21

1

Much prettier than the other solutions – Erik Aronesty Nov 30 '18 at 14:07
5

@ErikAronesty While you should pay attention to the `null` and boolean values (true/false). They are JSON values not the python objects. – Ryan Chou Dec 03 '18 at 02:56
2

Okay solution for simple cases, but converts python values to json values (as @RyanChou pointed out) and it might not be desirable or possible (like with `datetime`): `json.dumps({'d': datetime.now()})` will crash with `Object of type datetime is not JSON serializable`. – Andrey Dec 31 '19 at 11:48
`NameError: name 'json' is not defined` - Is this a module that needs importing? If so, would you mind updating your answer to reflect that? – Jack_Hu Apr 08 '21 at 11:05

score 29 · Answer 3 · answered May 06 '14 at 14:12

29

If you are trying to pretty print the environment variables, use:

pprint.pprint(dict(os.environ), width=1)

answered May 06 '14 at 14:12

UngodlySpoon

311
4
5

score 4 · Answer 4 · answered Mar 15 '19 at 09:43

4

Two things to add on top of Ryan Chou's already very helpful answer:

pass the sort_keys argument for an easier visual grok on your dict, esp. if you're working with pre-3.6 Python (in which dictionaries are unordered)

print(json.dumps(item, indent=4, sort_keys=True))
"""
{
    "first": 123,
    "second": 456,
    "third": {
        "1": 1,
        "2": 2
    }
}
"""

dumps() will only work if the dictionary keys are primitives (strings, int, etc.)

answered Mar 15 '19 at 09:43

Zach Valenta

1,783
1
20
35

Neat! `sort_keys` is a great argument. Unfortunately, as you say not always applicable: `TypeError: Object of type Tag is not JSON serializable`... – PatrickT May 21 '20 at 20:55

JayRizzo · Answer 5 · 2023-01-14T15:24:27.933

This is a Copy-Pasta for testing purposes and to help with a usage example.

from pprint import pprint  # I usually only need this module from the package. 

a = {'first': 123, 'second': 456, 'third': {1:1, 2:2}, 'zfourth': [{3:9, 7:8}, 'distribution'], 1:2344, 2:359832, 3:49738428, 4:'fourth', 5:{'dictionary':'of things', 'new':['l','i','s','t']}}

pprint(dict(a), indent=4, width=1)

# Wrap your variable in dict() function
# Optional: indent=4. for readability
# Required: width=1 for wrapping each item to its own row.
# Note: Default pprint is to sort the dictionary
# Note: This also auto-wraps anything sting that has spaces in it.  See 'of things' below.

# Documentation:  https://docs.python.org/3/library/pprint.html
# Examples:       https://pymotw.com/2/pprint/
# Blog:           https://realpython.com/python-pretty-print/

Provides the following result:

{   1: 2344,
    2: 359832,
    3: 49738428,
    4: 'fourth',
    5: {   'dictionary': 'of '
                         'things',
           'new': [   'l',
                      'i',
                      's',
                      't']},
    'first': 123,
    'second': 456,
    'third': {   1: 1,
                 2: 2},
    'zfourth': [   {   3: 9,
                       7: 8},
                   'distribution']}

I don't understand how this is intended to a) answer the question; b) add any information that isn't thoroughly covered by existing answers. — Karl Knechtel, Jan 14 '23 at 15:29
This helps as it is just a different perspective with a copy paste option. As sometimes snippets do not exactly convey the point to new learners. — JayRizzo, Jan 14 '23 at 15:31

pprint dictionary on multiple lines

5 Answers5

Linked

Related