Cron Step Value Extraction Regex for Python

What this pattern does

This page provides a well-structured, multi-part regular expression for matching cron step value extraction, ported and verified for Python. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your Python project — whether you're validating in a Django view, a FastAPI endpoint, or a standalone data processing script.

Python Implementation

# Cron Step Value Extraction
# ReDoS-safe | RegexVault — Dev & Systems > Cron

import re

cron_step_value_extraction_pattern = re.compile(r'(?:\*|[0-9]{1,2}(?:-[0-9]{1,2})?)/([1-9][0-9]?)')

def validate_cron_step_value_extraction(value: str) -> bool:
    return bool(cron_step_value_extraction_pattern.fullmatch(value))

# Example
print(validate_cron_step_value_extraction("*/15"))  # True

Test Cases

When to use this pattern

This pattern is drawn from the Dev & Systems > Cron category and carries a ReDoS-safe certification. That matters for Python developers because particularly important in Python web servers where CPU-bound regex operations can stall concurrent request handling. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

Capture group 1 contains the step value. Used for programmatic extraction of schedule frequency. A step must always follow either * or a range.