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Coding questions · Amazon

Identify Date with Highest Total kWh Consumption Using Pandas

This question evaluates proficiency in pandas-based data manipulation and time-series aggregation, specifically the competency to aggregate and summarize meter readings to identify peak consumption dates.

meter_readings

+----------+------------+---------------+---------+
| meter_id | timestamp  | kwh_consumed  | city    |
+----------+------------+---------------+---------+
| 1001     | 2023-01-01 | 15.2          | Austin  |
| 1001     | 2023-01-02 | 18.0          | Austin  |
| 1002     | 2023-01-01 | 22.5          | Dallas  |
| 1002     | 2023-01-02 | 20.1          | Dallas  |
| 1003     | 2023-01-01 | 10.7          | Houston |
+----------+------------+---------------+---------+
Scenario

Analyst needs to summarize smart-meter readings for an operations report.

Question

Using pandas, aggregate total kwh_consumed for each date and return the date with the highest total consumption.

Hints

groupby on timestamp, sum, use idxmax or sort_values.

Find date with highest total kWh consumption

Given the meter_readings table of smart-meter data, write an SQL query to aggregate the total kwh_consumed for each date (timestamp) across all meters, and return the single date with the highest total consumption along with that total.

Table meter_readings

columntypeconstraints
meter_idINTEGER
timestampDATE
kwh_consumedDECIMAL(10,1)
cityVARCHAR(50)

Sample data:

citykwh_consumedmeter_idtimestamp
Austin15.210012023-01-01
Austin1810012023-01-02
Dallas22.510022023-01-01
Dallas20.110022023-01-02
Houston10.710032023-01-01

Expected output

A single row containing the date (timestamp) with the highest summed kWh across all meters and the corresponding total kWh consumed on that date.

timestamptotal_kwh_consumed
2023-01-0148.4

Hints

  1. GROUP BY timestamp and SUM kwh_consumed
  2. ORDER BY the summed value in descending order and LIMIT 1