ski wrote:
hello,
i have this list which contains a number of dictionaries.
>>>d1 = [{'is_selected': False, 'id': 'AAC', 'title': 'Association of
Airline Cons.'}, {'is_selected': False, 'id': 'AALA', 'title': 'Adv.
Activity Licence. Auth.'}, {'is_selected': False, 'id': 'ABPCO',
'title': 'Association of British Prof. Conf. Organisation'},
{'is_selected': True, 'id': 'ABTA', 'title': 'Association of British
Travel Agents'}, {'is_selected': False, 'id': 'ABTOT', 'title':
'Association of Bonded Travel Organisation Trust'}, {'is_selected':
False, 'id': 'AERA', 'title': 'Association of Europe Rail Agents'}]
what would be the correct way to create a new list with the dictionaries
but only for dictionaries with key
'is_selected': False
here is what I have tried, so far, perhaps there is a better and less
error prone method:
>>> d2 = []
>>> for x in d1:
... if False in x.values():
... d2.append(x)
This code is wrong, x.values() gives a list of values in the dictionary x, and
if 'False' is in it, you append the dict. You never check for the key.
Thus
d1 = [ {'id':False} ]
would also be copied.
Also, if you have a dict, and you know which key to use, use that key!!
Key-lookup in a dict is very much faster than a linear search in a list like
x.values().
You can do something like
[d for d in d1 if d['is_selected'] == False]
to get your dicts.
If 'is_selected' is not always present, it gets a bit more complicated, I'll
leave that as an exercise for the interested reader :)
Sincerely,
Albert
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