What is the most pythonic way to convert:
A = [a1, a2, a3, a4, a5]
where "A" can be a list with any number of elements to
B = {a1: {a2: {a3: {a4: {a5: y}}}}}
where y is some variable.
Asked
Active
Viewed 74 times
3
falsetru
- 357,413
- 63
- 732
- 636
-
1*Creating* the nested dictionaries or simply *traversing* the existing indexable object graph? – user2864740 Sep 08 '14 at 07:07
-
creating a nested dictionary – Sep 08 '14 at 07:10
-
but what do you mean by 'simply traversing the existing indexable object graph' – Sep 08 '14 at 07:18
-
Eg. reading or setting the value in an already existing nested-array/dictionary structure (such as from some deserialized JSON). – user2864740 Sep 08 '14 at 07:22
-
possible duplicate of [Python list to nested keys](http://stackoverflow.com/questions/25326180/python-list-to-nested-keys) – tobias_k Sep 08 '14 at 08:07
1 Answers
3
def build_dict(A, y):
for s in reversed(A):
y = {s: y}
return y
A = ['a1', 'a2', 'a3', 'a4', 'a5']
y = 'some value'
print(build_dict(A, y))
output:
{'a1': {'a2': {'a3': {'a4': {'a5': 'some value'}}}}}
Alternative using reduce (functools.reduce in Python 3.x):
>>> A = ['a1', 'a2', 'a3', 'a4', 'a5']
>>> y = 'some value'
>>> reduce(lambda x, s: {s: x}, reversed(A), y)
{'a1': {'a2': {'a3': {'a4': {'a5': 'some value'}}}}}
falsetru
- 357,413
- 63
- 732
- 636