Pandas Data Manipulation Approach | Dataford Interview Questions

Can you explain how you would approach a data manipulation task using Pandas?

For this SQL version, use the supplied instrument and observation data to produce a concise summary for active instruments. Include only observations from January 2025 and preserve active instruments that have no matching observations.

Output

One row per active instrument, with instrument_code, instrument_name, valid_observations, average_observation, latest_observation, and observation_band.
Classify averages of at least 100 as High, lower averages as Standard, and instruments without valid observations as No data.
Order by instrument_code ascending.

Schema

instruments

Column	Type	Description
instrument_idPK	INT	Unique instrument identifier
instrument_code	VARCHAR(20)	Instrument display code
instrument_name	VARCHAR(100)	Instrument name
is_active	BOOLEAN	Whether the instrument is currently active

observations

Column	Type	Description
observation_idPK	INT	Unique observation identifier
instrument_id	INT	Referenced instrument
observed_at	DATE	Observation date
observed_value	DECIMAL(10,2)	Measured observation value

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Problem