#0007

Safely Read a Nested Dictionary Value

MediumPython16 min15 XP

Problem

Given a dictionary, a list of keys, and a default value, walk through the nested dictionaries. Return the found value or the default if any key is missing.

Why This Matters

API responses and JSON data are nested. Production code needs to handle missing keys gracefully.

Function Signature

def nested_get(data, keys, default=None):

Examples

Example 1

Inputdata = {"user": {"profile": {"city": "Chennai"}}}, keys = ["user", "profile", "city"]

Output"Chennai"

Every key exists, so the nested value is returned.

Constraints

Intermediate levels must be dictionaries.
Return default if any key is missing.
An empty keys list returns the original data.

CodePython

def nested_get(data, keys, default=None):
    """
    Input example: data = {"user": {"profile": {"city": "Chennai"}}}, keys = ["user", "profile", "city"]
    Return: "Chennai"
    Return the value from the function so the tests can compare it. Do not print unless the prompt asks.
    """
    # write your code here
    return default

def nested_get(data, keys, default=None):
    """
    Input example: data = {"user": {"profile": {"city": "Chennai"}}}, keys = ["user", "profile", "city"]
    Return: "Chennai"
    Return the value from the function so the tests can compare it. Do not print unless the prompt asks.
    """
    # write your code here
    return default

Visible browser tests run here when available.

Testcases2 visible / 4 hidden categories

Existing nested value

Inputcity inside user/profile

Expected"Chennai"

The function walks one key at a time.

Missing nested key

Inputcountry missing inside profile

Expected"NA"

Missing keys return the default instead of raising KeyError.

Hidden Test Categories

Empty keys listIntermediate value is not a dictionaryDefault value is NoneOne-level dictionary