Compile a regex pattern for validating or extracting US Social Security Numbers.

Validate or extract SSN strings in data validation, cleaning, or PII handling tasks.

Validating user input for SSN fields, cleaning PII datasets, validating data imports, log parsing for SSN patterns.

Data validation, data cleaning, PII handling, form validation, log parsing.

re.compile(r'^\d{3}-\d{2}-\d{4}$')

re.compile(...)

area_number: int (exactly 3 digits), group_number: int (exactly 2 digits), serial_number: int (exactly 4 digits)

• SSN
• social security number
• validate
• re.match
• re.search
• re.fullmatch
• input validation
• PII

• r'\d{3}-\d{2}-\d{4}' (without anchors)
• r'\d{9}' (condensed)
• r'\d{3}\s?\d{2}\s?\d{4}' (optional spaces)

Omitting ^ and $ anchors leading to partial matches; using \d{9} ignoring hyphens; using \d{3}-\d{2}-\d{4} but allowing extra characters before/after; forgetting raw string r'...' in Python causing incorrect escape sequences.

US phone number regex r'^\d{3}-\d{3}-\d{4}$' (different grouping); US ZIP+4 regex r'^\d{5}(-\d{4})?$' (different length); Canadian SIN regex r'^\d{3}\s?\d{3}\s?\d{3}$' (different separator and grouping).

Coming from JavaScript: forgetting to use raw string r'...' in Python causing incorrect escape interpretation; Coming from Java: forgetting to compile pattern with re.compile and using String.matches incorrectly; Coming from JavaScript: using \d without escaping backslash in string literal.

• regex patterns
• validation patterns
• PII validation
• SSN validation

Do not rely solely on this regex for SSN validity as it does not check prohibited ranges (e.g., all zeros, 666, or 900-999 series); Pre‑compiling with re.compile yields significant performance gains when matching many strings; The pattern strictly enforces hyphen separators and rejects spaces or other separators.

Using a pre‑compiled SSN regex ensures fast, reliable format validation, preventing malformed SSNs from entering databases and reducing downstream validation errors.

Think of the pattern as a telephone‑line format: three digits, a dash, two digits, another dash, then four digits — just like a phone number but with different grouping.

This regex validates format only; it does not verify that the number is a genuine issued SSN (e.g., not in the SSA's high‑group list).

Consider adding SSN range validation (e.g., reject 000-##-####, 666-##-####, 900-999-##-####) or using a library that validates against the SSA's high‑group list.