Fetching nested value given dot notation

Question

I have the following structure in my json:

obj = {
  'Name': 'David',
  'Car': {
           'Make': 'Ford',
           'Year': 2008
   }
}

I am given dot notation to refer to the object value, for example:

Car.Make ==> 'Form'

Given a string, such as "Car.Make", how would I programmatically fetch the attribute? In the above example, it would be:

obj.get('Car').get('Make')

But what about for a deeply-nested object, how would I extract the value given dot notation of "Attr1.Attr2.Attr3...Attrn" ?

I don't think there's going to be a solution that's syntactically valid for both Java and Python. — Kevin, Sep 04 '15 at 18:13

score 5 · Accepted Answer · answered Sep 04 '15 at 18:16

obj = {
  'Name': 'David',
  'Car': {
           'Make': 'Ford',
           'Year': 2008
   }
}
s = "Car.Make"
x = obj
keys = s.split(".")
for key in keys:
    x = x[key]
print(x)

Result:

Ford

Or, in one-liner form:

from functools import reduce
print(reduce(lambda a,b: a[b], s.split("."), obj))

score 0 · Answer 2 · edited May 23 '17 at 12:22

0

Here are some answers from Stackoverflow that propose a custom dictionary class that implements __getattr__ and __setattr__ to access the dictionary items:

edited May 23 '17 at 12:22

Community

1
1

answered Sep 04 '15 at 18:19

jojonas

1,634
14
24

I missed the fact that you are given a string, sorry! – jojonas Sep 04 '15 at 18:20

Fetching nested value given dot notation

2 Answers2

Linked

Related