I'm trying to run a Python script using cron in Linux, which should construct a dictionary of data. I'm attempting to use datetime().now().time()
as keys in the dictionary, but it seems to raise an error.
Can't the datetime
type be used as a dictionary key in Python? If that is the case, what are my alternatives?
Code:
time_now = dt.datetime.now().time()
date_today = dt.datetime.now().date()
usage_dict_hourly = {}
date_wise_dict = {}
def constructing_dict(data_int):
date_wise_dict[usage_dict_hourly[time_now]] = data_int
print date_wise_dict
Error:
<ipython-input-9-ef6a500cc71b> in constructing_dict(data_int)
36
37 def constructing_dict(data_int):
---> 38 date_wise_dict[usage_dict_hourly[time_now]] = data_int
39 print date_wise_dict
40
KeyError: datetime.time(22, 40, 33, 746509)
Answering your question about datetime as a dictionary key:
Yes, time object of datetime can be used as dictionary key.
Conditions to use an object as a dictionary key:
To be used as a dictionary key, an object must support the hash function (e.g. through
__hash__
), equality comparison (e.g. through__eq__
or__cmp__
)(...)
(Source: DictionaryKeys)
datetime support for cited conditions:
Supported operations:
...
- hash, use as dict key
(Source: datetime - time Objects)
However, you are getting this exception because dict usage_dict_hourly
is empty.
usage_dict_hourly
is initiated with {}
. So, when you try to look for the element with key time_now
in your function constructing_dict
, it raises KeyError
exception, because that key has not been found.