Reputation: 1477
From another function, I have tuples like this ('falseName', 'realName', positionOfMistake)
, eg. ('Milter', 'Miller', 4)
.
I need to write a function that make a dictionary like this:
D={realName:{falseName:[positionOfMistake], falseName:[positionOfMistake]...},
realName:{falseName:[positionOfMistake]...}...}
The function has to take a dictionary and a tuple like above, as arguments.
I was thinking something like this for a start:
def addToNameDictionary(d, tup):
dictionary={}
tup=previousFunction(string)
for element in tup:
if not dictionary.has_key(element[1]):
dictionary.append(element[1])
elif:
if ...
But it is not working and I am kind of stucked here.
Upvotes: 21
Views: 114767
Reputation: 5616
If it is only to add a new tuple and you are sure that there are no collisions in the inner dictionary, you can do this:
def addNameToDictionary(d, tup):
if tup[0] not in d:
d[tup[0]] = {}
d[tup[0]][tup[1]] = [tup[2]]
Upvotes: 17
Reputation: 7745
dictionary's setdefault is a good way to update an existing dict entry if it's there, or create a new one if it's not all in one go:
Looping style:
# This is our sample data
data = [("Milter", "Miller", 4), ("Milter", "Miler", 4), ("Milter", "Malter", 2)]
# dictionary we want for the result
dictionary = {}
# loop that makes it work
for realName, falseName, position in data:
dictionary.setdefault(realName, {})[falseName] = position
dictionary now equals:
{'Milter': {'Malter': 2, 'Miler': 4, 'Miller': 4}}
Upvotes: 8
Reputation:
Using collections.defaultdict
is a big time-saver when you're building dicts and don't know beforehand which keys you're going to have.
Here it's used twice: for the resulting dict, and for each of the values in the dict.
import collections
def aggregate_names(errors):
result = collections.defaultdict(lambda: collections.defaultdict(list))
for real_name, false_name, location in errors:
result[real_name][false_name].append(location)
return result
Combining this with your code:
dictionary = aggregate_names(previousFunction(string))
Or to test:
EXAMPLES = [
('Fred', 'Frad', 123),
('Jim', 'Jam', 100),
('Fred', 'Frod', 200),
('Fred', 'Frad', 300)]
print aggregate_names(EXAMPLES)
Upvotes: 12