Python re module provides full regex support with search(), match(), findall(), and sub().
Essential patterns: \\d for digits, \\w for word characters, \\s for whitespace. Quantifiers: +, *, {n,m}. Anchors: ^, $. Groups: (pattern).
Email validation: r'^[\\w.-]+@[\\w.-]+\\.\\w+$'. URL extraction: r'https?://[^\\s]+'.
re.compile() pre-compiles patterns for reuse. re.VERBOSE allows multi-line patterns with comments.
Common pitfalls: greedy vs lazy quantifiers, catastrophic backtracking, and forgetting . does not match newlines by default.
For complex parsing, consider whether regex is the right tool. Sometimes a proper parser is more maintainable.