I'd like to create a dictionary inside a dictionary in python using function setdefault()
. I'm trying to make a list of names and dates of birth using fallow dictionary.
names = {'Will': 'january', 'Mary': 'february', 'George': 'march', 'Steven': 'april', 'Peter': 'may'}
dates = {'Will': '7/01', 'George': '21/03', 'Steven': '14/03', 'Mary': '2/02'}
I was tring to use set to achieve this:
res_dict = dict()
for v, k in names.items():
for v1, k1 in dates.items():
res_dict.setdefault(v, {}).append(k)
res_dict.setdefault(v1, {}).append(k1)
return res_dict
but it give me an error.
The result should be:
res_dict = {'Will': {'january': '7/01'}, 'Mary' : {'february': '2/02'} ,'George': {'march': '21/03'}, 'Steven': {'april': '14/03'}, 'Peter': {'may': ''}}
How can I get the desired result using setdefault()
?
You could try this:
In [17]: results = {}
In [18]: for k, v in names.iteritems():
results[k] = {v: dates.setdefault(k, '')}
....:
....:
In [20]: results
Out[20]:
{'George': {'march': '21/02'},
'Mary': {'february': '2/02'},
'Peter': {'may': ''},
'Steven': {'april': '14/03'},
'Will': {'january': '7/01'}}
And as to your comment regarding adding month
and day
, you can add them similarly:
In [28]: for k, v in names.iteritems():
results[k] = {'month': v, 'day': dates.setdefault(k, '')}
....:
....:
In [30]: results
Out[30]:
{'George': {'day': '21/02', 'month': 'march'},
'Mary': {'day': '2/02', 'month': 'february'},
'Peter': {'day': '', 'month': 'may'},
'Steven': {'day': '14/03', 'month': 'april'},
'Will': {'day': '7/01', 'month': 'january'}}
And if you want to omit day
completely in the case where a value doesn't exist:
In [8]: results = {}
In [9]: for k, v in names.iteritems():
...: results[k] = {'month': v}
...: if dates.has_key(k):
...: results[k]['day'] = dates[k]
...:
...:
In [10]: results
Out[10]:
{'George': {'day': '21/03', 'month': 'march'},
'Mary': {'day': '2/02', 'month': 'february'},
'Peter': {'month': 'may'},
'Steven': {'day': '14/03', 'month': 'april'},
'Will': {'day': '7/01', 'month': 'january'}}
And in the odd case where you know the date but not the month, iterating through the set of the keys (as @KayZhu suggested) with a defaultdict
may be the easiest solution:
In [1]: from collections import defaultdict
In [2]: names = {'Will': 'january', 'Mary': 'february', 'George': 'march', 'Steven': 'april', 'Peter': 'may'}
In [3]: dates = {'Will': '7/01', 'George': '21/03', 'Steven': '14/03', 'Mary': '2/02', 'Marat': '27/03'}
In [4]: results = defaultdict(dict)
In [5]: for name in set(names.keys() + dates.keys()):
...: if name in names:
...: results[name]['month'] = names[name]
...: if name in dates:
...: results[name]['day'] = dates[name]
...:
...:
In [6]: for k, v in results.iteritems():
...: print k, v
...:
...:
George {'day': '21/03', 'month': 'march'}
Will {'day': '7/01', 'month': 'january'}
Marat {'day': '27/03'}
Steven {'day': '14/03', 'month': 'april'}
Peter {'month': 'may'}
Mary {'day': '2/02', 'month': 'february'}
A simple one-liner:
In [38]: names = {'Will': 'january', 'Mary': 'february', 'George': 'march', 'Steven': 'april', 'Peter': 'may'}
In [39]: dates = {'Will': '7/01', 'George': '21/03', 'Steven': '14/03', 'Mary': '2/02'}
In [40]: dict((name,{names[name]:dates.get(name,'')}) for name in names)
out[40]:
{'George': {'march': '21/03'},
'Mary': {'february': '2/02'},
'Peter': {'may': ''},
'Steven': {'april': '14/03'},
'Will': {'january': '7/01'}}
You will need get the superset keys from names
and dates
first:
>>> for k in set(names.keys() + dates.keys()):
... res_dict[k] = {names.setdefault(k, ''): dates.setdefault(k, None)}
...
...
>>> res_dict
{'Will': {'january': '7/01'}, 'Steven': {'april': '14/03'}, 'Peter': {'may': None},
'Mary': {'february': '2/02'}, 'George': {'march': '21/03'}}
Otherwise, you will miss out results whose keys are in dates
but not in names
.
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