Python pretty print dictionary of lists, abbreviate long lists
You could use IPython.lib.pretty.
from IPython.lib.pretty import pprint
> pprint(obj, max_seq_length=5)
{'key_1': ['EG8XYD9FVN',
'S2WARDCVAO',
'J00YCU55DP',
'R07BUIF2F7',
'VGPS1JD0UM',
...],
'key_2': ['162LO154PM',
'3ROAV881V2',
'I4T79LP18J',
'WBD36EM6QL',
'DEIODVQU46',
...]}
> pprint(dict(map(lambda i: (i, range(i + 5)), range(100))), max_seq_length=10)
{0: [0, 1, 2, 3, 4],
1: [0, 1, 2, 3, 4, 5],
2: [0, 1, 2, 3, 4, 5, 6],
3: [0, 1, 2, 3, 4, 5, 6, 7],
4: [0, 1, 2, 3, 4, 5, 6, 7, 8],
5: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
6: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ...],
7: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ...],
8: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ...],
9: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ...],
...}
For older versions of IPython, you might exploit RepresentationPrinter:
from IPython.lib.pretty import RepresentationPrinter
import sys
def compact_pprint(obj, max_seq_length=10):
printer = RepresentationPrinter(sys.stdout)
printer.max_seq_length = max_seq_length
printer.pretty(obj)
printer.flush()
If it weren't for the pretty printing, the reprlib
module would be the way to go: Safe, elegant and customizable handling of deeply nested and recursive / self-referencing data structures is what it has been made for.
However, it turns out combining the reprlib
and pprint
modules isn't trivial, at least I couldn't come up with a clean way without breaking (some) of the pretty printing aspects.
So instead, here's a solution that just subclasses PrettyPrinter
to crop / abbreviate lists as necessary:
from pprint import PrettyPrinter
obj = {
'key_1': [
'EG8XYD9FVN', 'S2WARDCVAO', 'J00YCU55DP', 'R07BUIF2F7', 'VGPS1JD0UM',
'WL3TWSDP8E', 'LD8QY7DMJ3', 'J36U3Z9KOQ', 'KU2FUGYB2U', 'JF3RQ315BY',
],
'key_2': [
'162LO154PM', '3ROAV881V2', 'I4T79LP18J', 'WBD36EM6QL', 'DEIODVQU46',
'KWSJA5WDKQ', 'WX9SVRFO0G', '6UN63WU64G', '3Z89U7XM60', '167CYON6YN',
],
# Test case to make sure we didn't break handling of recursive structures
'key_3': [
'162LO154PM', '3ROAV881V2', [1, 2, ['a', 'b', 'c'], 3, 4, 5, 6, 7],
'KWSJA5WDKQ', 'WX9SVRFO0G', '6UN63WU64G', '3Z89U7XM60', '167CYON6YN',
]
}
class CroppingPrettyPrinter(PrettyPrinter):
def __init__(self, *args, **kwargs):
self.maxlist = kwargs.pop('maxlist', 6)
return PrettyPrinter.__init__(self, *args, **kwargs)
def _format(self, obj, stream, indent, allowance, context, level):
if isinstance(obj, list):
# If object is a list, crop a copy of it according to self.maxlist
# and append an ellipsis
if len(obj) > self.maxlist:
cropped_obj = obj[:self.maxlist] + ['...']
return PrettyPrinter._format(
self, cropped_obj, stream, indent,
allowance, context, level)
# Let the original implementation handle anything else
# Note: No use of super() because PrettyPrinter is an old-style class
return PrettyPrinter._format(
self, obj, stream, indent, allowance, context, level)
p = CroppingPrettyPrinter(maxlist=3)
p.pprint(obj)
Output with maxlist=3
:
{'key_1': ['EG8XYD9FVN', 'S2WARDCVAO', 'J00YCU55DP', '...'],
'key_2': ['162LO154PM',
'3ROAV881V2',
[1, 2, ['a', 'b', 'c'], '...'],
'...']}
Output with maxlist=5
(triggers splitting the lists on separate lines):
{'key_1': ['EG8XYD9FVN',
'S2WARDCVAO',
'J00YCU55DP',
'R07BUIF2F7',
'VGPS1JD0UM',
'...'],
'key_2': ['162LO154PM',
'3ROAV881V2',
'I4T79LP18J',
'WBD36EM6QL',
'DEIODVQU46',
'...'],
'key_3': ['162LO154PM',
'3ROAV881V2',
[1, 2, ['a', 'b', 'c'], 3, 4, '...'],
'KWSJA5WDKQ',
'WX9SVRFO0G',
'...']}
Notes:
- This will create copies of lists. Depending on the size of the data structures, this can be very expensive in terms of memory use.
- This only deals with the special case of lists. Equivalent behavior would have to be implemented for dicts, tuples, sets, frozensets, ... for this class to be of general use.