stats-aggregator

name	stats-aggregator
description	Compute aggregate statistics (mean, median, sum, count, min, max) grouped by a column.
version	1.0.0

Stats Aggregator

Skill Summary

Groups records by a specified column and computes configurable aggregate statistics on a numeric value column. Supports six standard statistical metrics: mean, median, sum, count, min, and max.

Inputs

• --input / -i: Path to JSON records file (required)
• --group-by / -g: Column name to group records by (required)
• --value-column / -v: Numeric column to aggregate (required)
• --metrics: Comma-separated metrics to compute (default: mean,median,sum,count,min,max)
• --output / -o: Output directory (required)

Available Metrics

Metric	Description	Python Function
mean	Arithmetic mean	statistics.mean()
median	Middle value	statistics.median()
sum	Sum of all values	sum()
count	Number of records	len()
min	Minimum value	min()
max	Maximum value	max()

Processing Steps

1. Load JSON records from input file
2. Group records by the specified column
3. For each group, extract the value column as a list of floats
4. Compute each requested metric
5. Write results to stats_report.json

Output

• stats_report.json with structure:

  {
    "group_column": "region",
    "groups": {
      "North": {"mean": 150.5, "median": 140.0, "sum": 3010, "count": 20, "min": 80, "max": 250},
      "South": {"mean": 120.3, ...}
    }
  }
  

Implementation

• Command: python3 stats-aggregator/aggregator.py -i <file> -g region -v revenue -o <dir>
• Dependencies: Python standard library (json, statistics, argparse, os)