Smoothing the values of each key in python
I have a dictionary like this:
migration_dict = {'30005': ['key42750','key43119', 'key44103', ['key333'],
['key444'], ['keyxx']], '30003': ['key43220', 'key42244','key42230',
['keyzz'], ['kehh']]}
How can I flatten the values of each key to have something like this:
migration_dict = {'30005': ['key42750','key43119', 'key44103', 'key333',
'key444', 'keyxx'], '30003': ['key43220', 'key42244','key42230',
'keyzz', 'kehh']}
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You can write a recursive function to flatten lists of values and use it in dictionary comprehension to create a new dictionary:
def flatten(lst):
for x in lst:
if isinstance(x, list):
for y in flatten(x): # yield from flatten(...) in Python 3
yield y #
else:
yield x
migration_dict = {k: list(flatten(v)) for k, v in dct.items()}
print(migration_dict)
# {'30005': ['key42750', 'key43119', 'key44103', 'key333', 'key444', 'keyxx'], '30003': ['key43220', 'key42244', 'key42230', 'keyzz', 'kehh']}
It handles any nesting depth in lists of dict values.
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for key in migration_dict:
for i in migration_dict[key]:
if type(i) == list:
migration_dict[key].remove(i)
for element in i:
migration_dict[key].append(element)
This loop should now do it. Note, however, that this only works if the inner list contains no more lists. If this happens, you might have to make a recursive function that flattens it out for you.
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If you don't mind using a third party extension, you can use 1 and dictation comprehension:iteration_utilities.deepflatten
>>> from iteration_utilities import deepflatten
>>> {key: list(deepflatten(value, ignore=str)) for key, value in migration_dict.items()}
{'30003': ['key43220', 'key42244', 'key42230', 'keyzz', 'kehh'],
'30005': ['key42750', 'key43119', 'key44103', 'key333', 'key444', 'keyxx']}
This will align all duplicate items in your values (except for strings).
1 Disclaimer: I am the author of this library
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Here he is:
Consider this dict, the same structure:
m = {'a': ['k1', 'k2', 'k3', ['k4'], ['k5'], ['k6']],
'b': ['k1', 'k2', 'k3', ['k4'], ['k5'], ['k6']]}
import itertools
d = {k:list(itertools.chain.from_iterable(itertools.repeat(x,1) if isinstance(x, str) else x for x in v)) for k,v in m.iteritems()}
{'a': ['k1', 'k2', 'k3', 'k4', 'k5', 'k6'],
'b': ['k1', 'k2', 'k3', 'k4', 'k5', 'k6']}
You can also use a third party library more-iterools
,
t = {k: list(more_itertools.collapse(v, base_type=str)) for k,v in m.iteritems()}
{'a': ['k1', 'k2', 'k3', 'k4', 'k5', 'k6'],
'b': ['k1', 'k2', 'k3', 'k4', 'k5', 'k6']}
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If it's important to have flat values in your dictionary, perhaps you could create a function that will get rid of all (multidimensional) lists before adding them to the dictionary?
def flatten_values(value):
if type(value) == list:
for i in value:
return i
Hope it helps, can't do it in comment because I don't have enough rep;)
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