Reverse Month Converter

Reverse Month Converter

Overview

Convert dates from various human-readable formats into standardized "reverse month" format (YYYY-MM). This skill handles flexible date input parsing and provides consistent, machine-readable month output by extracting only the year and month components from a full date.

The reverse month format is the year and month portion of an ISO date (YYYY-MM), making it ideal for monthly reporting, time-series aggregations, and calendar operations.

Usage

Use the convert_month.py script to convert any date string to YYYY-MM format:

python scripts/​convert_month.py "21 Oct 2025"
# Output: 2025-10

Supported Input Formats

The script accepts a wide variety of date formats, including:

• Month-day-year: "21 Oct 2025", "October 21, 2025", "Oct 21, 2025"
• Slash-separated: "21/​10/​2025", "10/​21/​2025"
• Dash-separated: "21-10-2025", "2025-10-21"
• ISO format: "2025-10-21"
• Other common formats: Most standard date representations

Examples

# Human-readable format
python scripts/​convert_month.py "21 Oct 2025"
# → 2025-10

# Full month name
python scripts/​convert_month.py "October 21, 2025"
# → 2025-10

# Slash format
python scripts/​convert_month.py "21/​10/​2025"
# → 2025-10

# Already in ISO format
python scripts/​convert_month.py "2025-10-21"
# → 2025-10

# Short format
python scripts/​convert_month.py "Oct 2025"
# → 2025-10

Error Handling

If the date string cannot be parsed, the script returns an error message:

python scripts/​convert_month.py "invalid date"
# Error: Unable to parse date: 'invalid date'. Error: Unknown string format: invalid date

Common Use Cases

• Monthly reporting and aggregations
• Calendar month filtering
• Time-series data grouping by month
• Standardizing month identifiers across different date formats
• Extracting billing or subscription periods

Relationship to reverse-date Skill

This skill builds upon the reverse-date skill concept. While reverse-date converts dates to full ISO format (YYYY-MM-DD), reverse-month extracts only the year-month portion (YYYY-MM), providing a coarser granularity suitable for monthly operations.

Implementation Details

The script uses Python's dateutil.parser library for flexible date parsing, which handles many common date formats automatically. The output is always in ISO 8601 year-month format (YYYY-MM).