Transform Nested JSON to Tables | Dataford Interview Questions

Write a function to handle data transformation from a nested JSON structure into a tabular format.

Implement flatten_json(data), where data is a list of JSON objects. Flatten nested objects by joining keys with ., and expand arrays of objects into separate rows. If multiple arrays occur in one object, produce the Cartesian product of their elements. Arrays of scalar values remain in a single cell. Return a list of dictionaries, with absent fields omitted.

The input contains JSON-compatible dictionaries, lists, strings, numbers, booleans, and null values. Preserve scalar values without conversion.

Constraints

1 <= len(data) <= 1000
Each top-level element is a JSON object
Object nesting depth is at most 10
Arrays are either empty, contain only JSON objects, or contain only scalar values
The output may contain up to 10000 rows after array expansion
Use dot notation to represent nested object paths

Function Signature

def flatten_json(data):

Your question is Transform Nested JSON to Tables. Start with the requirements in the Question tab.

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Problem

Write a function to handle data transformation from a nested JSON structure into a tabular format.

The input contains JSON-compatible dictionaries, lists, strings, numbers, booleans, and null values. Preserve scalar values without conversion.

Constraints

1 <= len(data) <= 1000
Each top-level element is a JSON object
Object nesting depth is at most 10
Arrays are either empty, contain only JSON objects, or contain only scalar values
The output may contain up to 10000 rows after array expansion
Use dot notation to represent nested object paths

Function Signature

def flatten_json(data):

Your question is Transform Nested JSON to Tables. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.