Regex Playground

Common Regex Patterns

• ^\d{3}-\d{2}-\d{4}$ – SSN
• [a-zA-Z_][a-zA-Z0-9_]* – Identifier
• \\b\\w+\\b – Word boundaries
• \\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}:\\d{2}Z – ISO UTC timestamp
• https?://[^\\s]+ – URL
• ^[^@\\s]+@[^@\\s]+\\.[^@\\s]+$ – Email
• \\s+ – One or more whitespace
• ^\\s*//.*$ – Single-line comment
• \\b(?:if|else|for|while|return)\\b – Reserved keywords
• (?=\\d{3})\\d{3} – Positive lookahead
• (?!\\d{3})\\d{3} – Negative lookahead
• (?<=\\$)\\d+(?:\\.\\d{2})? – Currency value
• (?\\d{4})-(?\\d{2})-(?\\d{2}) – Named groups
• ^\\w+(?=\\s|$) – First word only
• [^\\w]? – Non-word character optional