python: nested dictionary printing datetime as string

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I have a dictionary that looks something like

times = {
 'on': 
    {'start': datetime.time(6, 0, tzinfo=<DstTzInfo 'US/Eastern' LMT-1 day, 19:04:00 STD>), 
     'end': datetime.time(8, 0, tzinfo=<DstTzInfo 'US/Eastern' LMT-1 day, 19:04:00 STD>)}
 'off':
    {'start': datetime.time(10, 0, tzinfo=<DstTzInfo 'US/Eastern' LMT-1 day, 19:04:00 STD>), 
     'end': datetime.time(13, 0, tzinfo=<DstTzInfo 'US/Eastern' LMT-1 day, 19:04:00 STD>)}
}

calling str(times) gives

In[34]: str(f)
Out[34]: "{'on': {'start': datetime.time(6, 0, tzinfo=<DstTzInfo 'US/Eastern' LMT-1 day, 19:04:00 STD>), 'end': datetime.time(8, 0, tzinfo=<DstTzInfo 'US/Eastern' LMT-1 day, 19:04:00 STD>)}, 'off': {'start': datetime.time(10, 0, tzinfo=<DstTzInfo 'US/Eastern' LMT-1 day, 19:04:00 STD>), 'end': datetime.time(13, 0, tzinfo=<DstTzInfo 'US/Eastern' LMT-1 day, 19:04:00 STD>)}}"

when I would like the datetimes to output as

In[37]: str(times['on']['start'])
Out[37]: '06:00:00'

AKA:

"{'on': {'start': '06:00:00, 'end': '08:00:00'}, 'off': {'start': '10:00:00', 'end': '13:00:00'}}"

Is there a way to do this without creating a custom function?

user3030010 · Accepted Answer · 2016-10-26 16:25:10Z

2

This will do it:

str({k: {k1: str(v1) for k1, v1 in v.items()} for k, v in times.items()})

Output looks something like this:

"{'on': {'start': '10:01:00', 'end': '10:01:00'}, 'off': {'start': '10:01:00', 'end': '10:01:00'}}"

It's a little gross since you essentially have to un-pack and then re-pack a nested dictionary, but it works. For arbitrarily nested data, you would need a custom function.

answered Oct 26, 2016 at 16:25

user3030010

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DV82XL · Accepted Answer · 2021-12-29 21:46:21Z

2

This is much easier and works for any arbitrary dictionary:

import json

times = { ... }
s = json.dumps(times, default=str)
print(s)

answered Dec 29, 2021 at 21:46

DV82XL

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1 Comment

Eric Blum Over a year ago

huh, I never knew about dumps(default=)

Moinuddin Quadri · Accepted Answer · 2016-10-26 16:30:46Z

1

You need to use datetime.strftime() with format string as: "%H:%M:%S"

Hence, in order to update your dict, do:

for key, nested_dict in times.items():
    for k in nested_dict:
        nested_dict[k] = nested_dict[k].strftime("%H:%M:%S")

OR, use dict comprehension as:

{key: {k: v.strftime("%H:%M:%S") for k, v in nested_dict.items()} 
      for key, nested_dict in times.items()}

edited Oct 26, 2016 at 16:30

answered Oct 26, 2016 at 16:24

Moinuddin Quadri

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dawg · Accepted Answer · 2016-10-26 19:18:14Z

0

This is a great case for a subclass to control the string output of the time object:

You can do:

class MyTime(datetime.time):   
    def __repr__(self):
        return datetime.time.strftime(self, "%H:%M:%S")    


times = {
     'on': 
        {'start': MyTime(6, 0), 
         'end': MyTime(8, 0)},
     'off':
        {'start': MyTime(10, 0), 
         'end': MyTime(13, 0)}
    }

Then the formatting is automatic:

>>> times
{'on': {'start': 06:00:00, 'end': 08:00:00}, 'off': {'start': 10:00:00, 'end': 13:00:00}}

Yet the elements of your nested dict remain time objects:

>>> times['on']['start'].hour
6

edited Oct 26, 2016 at 19:18

answered Oct 26, 2016 at 16:32

dawg

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