Nested Dictionary values through dot path

get_key_dot_path.py

'''

get key values based on dot path

based on dict or json

d = {
        'd1': 1,
        'd2': {
            'a': 2, 'b': 3, },
        'd3': {
            'a': 4, 'b': {
                'a': 5, 'b': 6, }
        }
    }

+----------+-----------------+
| dot Path | Expected Output |
|==========+=================|
| "d1"     | 1               |
|----------+-----------------|
| "d2.b"   | 3               |
|----------+-----------------|
| "d3.b.b" | 6               |
|----------+-----------------|
| "d5"     | None            |
|----------+-----------------|
| "d1.b.b" | None            |
+----------+-----------------+


$> python3 get_key_dot_path.py
Using reduce
=1
=3
=6
=None
=None
in 6.604194641113281e-05 seconds

Using for loop
=1
=3
=6
=None
=None
in 4.6253204345703125e-05 seconds

Using recursion
=1
=3
=6
=None
=None
in 5.7220458984375e-05 seconds


CProfile
========

Using reduce
------------

15001 function calls in 0.010 seconds

   Random listing order was used

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
     5000    0.002    0.000    0.002    0.000 {method 'split' of 'str' objects}
     5000    0.003    0.000    0.003    0.000 {built-in method _functools.reduce}
     5000    0.005    0.000    0.010    0.000 get_key_dot_path.py:137(find_dot_path_reduce)
        1    0.000    0.000    0.000    0.000 {method 'disable' of '_lsprof.Profiler' objects}

Using for loop
--------------

23001 function calls in 0.011 seconds

   Random listing order was used

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
     8000    0.002    0.000    0.002    0.000 {method 'get' of 'dict' objects}
     5000    0.002    0.000    0.002    0.000 {method 'split' of 'str' objects}
     5000    0.001    0.000    0.001    0.000 {built-in method builtins.hasattr}
     5000    0.006    0.000    0.011    0.000 get_key_dot_path.py:149(find_dot_path_for)
        1    0.000    0.000    0.000    0.000 {method 'disable' of '_lsprof.Profiler' objects}

Using recursion
----------------

61001 function calls (57001 primitive calls) in 0.023 seconds

   Random listing order was used

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
     9000    0.002    0.000    0.002    0.000 {method 'pop' of 'list' objects}
     5000    0.001    0.000    0.001    0.000 {method 'reverse' of 'list' objects}
    12000    0.002    0.000    0.002    0.000 {method 'get' of 'dict' objects}
     5000    0.002    0.000    0.002    0.000 {method 'split' of 'str' objects}
     9000    0.001    0.000    0.001    0.000 {built-in method builtins.hasattr}
     7000    0.001    0.000    0.001    0.000 {built-in method builtins.len}
9000/5000    0.009    0.000    0.015    0.000 get_key_dot_path.py:121(get_key)
     5000    0.006    0.000    0.023    0.000 get_key_dot_path.py:117(find_dot_path)
        1    0.000    0.000    0.000    0.000 {method 'disable' of '_lsprof.Profiler' objects}

'''
import functools
import operator
import time


# using recursion
def find_dot_path(dct, s):
    keys_list = s.split('.')
    keys_list.reverse()

    def get_key(dct, keys):
        key = keys.pop()

        if not hasattr(dct, 'get'):
            return None

        value = dct.get(key, None)

        if value is None or len(keys_list) == 0:
            return value
        else:
            return get_key(dct.get(key), keys_list)
    return get_key(dct, keys_list)


# using reduce
def find_dot_path_reduce(dct, path):
    try:
        return functools.reduce(operator.getitem, path.split('.'), dct)
    except TypeError:
        # case value <> subscriptable type
        return None
    except KeyError:
        # case Key not Exists
        return None


# using a loop
def find_dot_path_for(dct, path):
    if hasattr(dct, '__getitem__'):
        keys = path.split('.')
        for key in keys:
            try:
                dct = dct.get(key, None)
            except AttributeError:
                return None
    return dct


import cProfile
import pstats

if __name__ == '__main__':
    d = {
        'd1': 1,
        'd2': {
            'a': 2, 'b': 3, },
        'd3': {
            'a': 4, 'b': {
                'a': 5, 'b': 6, }
        }
    }

    print(f'\nUsing reduce')
    start_time = time.time()
    print(f'={find_dot_path_reduce(d, "d1")}')
    print(f'={find_dot_path_reduce(d, "d2.b")}')
    print(f'={find_dot_path_reduce(d, "d3.b.b")}')
    print(f'={find_dot_path_reduce(d, "d5")}')
    print(f'={find_dot_path_reduce(d, "d1.b.b")}')
    print(f'in {time.time() - start_time} seconds')


    print(f'\nUsing for loop')
    start_time = time.time()
    print(f'={find_dot_path_for(d, "d1")}')
    print(f'={find_dot_path_for(d, "d2.b")}')
    print(f'={find_dot_path_for(d, "d3.b.b")}')
    print(f'={find_dot_path_for(d, "d5")}')
    print(f'={find_dot_path_for(d, "d1.b.b")}')
    print(f'in {time.time() - start_time} seconds')

    print(f'\nUsing recursion')
    start_time = time.time()
    print(f'={find_dot_path(d, "d1")}')
    print(f'={find_dot_path(d, "d2.b")}')
    print(f'={find_dot_path(d, "d3.b.b")}')
    print(f'={find_dot_path(d, "d5")}')
    print(f'={find_dot_path(d, "d1.b.b")}')
    print(f'in {time.time() - start_time} seconds')

    print(f'\nCProfile\n========')


    print(f'\nUsing reduce\n-------------')
    pr = cProfile.Profile()
    pr.enable()
    for k in range(1000):
            find_dot_path_reduce(d, "d1")
            find_dot_path_reduce(d, "d2.b")
            find_dot_path_reduce(d, "d3.b.b")
            find_dot_path_reduce(d, "d5")
            find_dot_path_reduce(d, "d1.b.b")
    pr.disable()
    ps = pstats.Stats(pr).print_stats()

    print(f'\nUsing for loop\n---------------')
    pr = cProfile.Profile()
    pr.enable()
    for k in range(1000):
            find_dot_path_for(d, "d1")
            find_dot_path_for(d, "d2.b")
            find_dot_path_for(d, "d3.b.b")
            find_dot_path_for(d, "d5")
            find_dot_path_for(d, "d1.b.b")
    pr.disable()
    ps = pstats.Stats(pr).print_stats()

    print(f'\nUsing recursion\n----------------')
    pr = cProfile.Profile()
    pr.enable()
    for k in range(1000):
            find_dot_path(d, "d1")
            find_dot_path(d, "d2.b")
            find_dot_path(d, "d3.b.b")
            find_dot_path(d, "d5")
            find_dot_path(d, "d1.b.b")
    pr.disable()
    ps = pstats.Stats(pr).print_stats()