Using reduce to navigate dictionaries and lists

navigation_with_reduce.py

# Demonstrate reduce to navigate a nested dictionary or list.

from functools import reduce
from operator import getitem

data_dict = {
    'a': 12,
    'b': [
        {
            'c': {
                'd': [
                    {
                        'e': 11,
                        'f': 72,
                        'g': 'etc'
                    },
                    {
                        'h': 42,
                        'i': 24
                    }
                ]
            }
        }, 
        {
            'extra': 32
        }
    ]
}

print(reduce(getitem, ['b', 0, 'c', 'd', 1, 'h'], data_dict))
# prints 42


data_list = [
    [
        [1, 2, 3, 4],
        [5, 6, 7, 8]
    ], [
        [9, 10, 11, 12],
        [13, 14, 15, 16]
    ]
]

print(reduce(getitem, [1, 0, 2], data_list))
# prints 11