Essential Regex Patterns for Validating Numbers, Text, and Common Data Formats

1. Number validation regexes

^[0-9]*$

– matches any number of digits. ^\d{n}$ – matches exactly n digits. ^\d{n,}$ – matches at least n digits. ^\d{m,n}$ – matches between m and n digits. ^(0|[1-9][0-9]*)$ – matches zero or a non‑zero number without leading zeros. ^([1-9][0-9]*)+(\.[0-9]{1,2})?$ – non‑zero number with up to two decimal places. ^(-)?\d+(\.\d{1,2})?$ – positive or negative number with optional 1‑2 decimal places. ^(-|\+)?\d+(\.\d+)?$ – signed integer or decimal. ^[0-9]+(\.[0-9]{2})?$ – integer or number with exactly two decimal places. ^[0-9]+(\.[0-9]{1,3})?$ – integer or number with 1‑3 decimal places. ^[1-9]\d*$ – positive integer without leading zero. ^-[1-9]\d*$ – negative integer without leading zero. ^\d+$ – non‑negative integer (including zero). ^(-[1-9]\d*|0)$ – non‑positive integer. ^\d+(\.\d+)?$ – non‑negative floating‑point number. ^(-?\d+(\.\d+)?)$ – non‑positive floating‑point number. ^[1-9]\d*\.\d*$ – positive floating‑point number. ^-([1-9]\d*\.\d*|0\.\d+)$ – negative floating‑point number. ^(-?\d+)(\.\d+)?$ – generic floating‑point number.

2. Character validation regexes

^[一-龥]{0,}$

– Chinese characters. ^[A-Za-z0-9]+$ – alphanumeric. ^[A-Za-z0-9]{4,40}$ – alphanumeric, length 4‑40. ^.{3,20}$ – any characters, length 3‑20. ^[A-Za-z]+$ – letters only. ^[A-Z]+$ – uppercase letters only. ^[a-z]+$ – lowercase letters only. ^[A-Za-z0-9]+$ – letters and digits. ^\w+$ or ^\w{3,20}$ – word characters (letters, digits, underscore). ^[一-龥A-Za-z0-9_]+$ – Chinese, letters, digits, underscore. ^[一-龥A-Za-z0-9]+$ – Chinese, letters, digits (no underscore). [^%&',;=?$"]+ – allows characters except common special symbols. [^~"]+ – disallows the tilde character.

3. Special‑requirement regexes

^\w+([-+.]*\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*$

– email address.

[a-zA-Z0-9][-a-zA-Z0-9]{0,62}(\.[a-zA-Z0-9][-a-zA-Z0-9]{0,62})+\.?$

– domain name. [a-zA-Z]+://[^\s]* or ^http://([\w-]+\.)+[\w-]+(/[\w-./?%&=]*)?$ – URL. ^(13[0-9]|14[57]|15[0-3,5-9]|18[0-9])\d{8}$ – Chinese mobile phone number. ^(\d{3,4}-)?\d{7,8}$ – telephone number with optional area code. \d{3}-\d{8}|\d{4}-\d{7} – domestic telephone formats. ^\d{15}|\d{18}$ – ID card number (15 or 18 digits). ^([0-9]{7,18})(x|X)?$ – short ID with optional trailing X. ^[a-zA-Z][a-zA-Z0-9_]{4,15}$ – username starting with a letter, 5‑16 characters. ^[a-zA-Z]\w{5,17}$ – password starting with a letter, 6‑18 characters. ^(?=.*\d)(?=.*[a-z])(?=.*[A-Z]).{8,10}$ – strong password (letters and digits, 8‑10 chars). ^\d{4}-\d{1,2}-\d{1,2}$ – date format YYYY‑M‑D. ^(0?[1-9]|1[0-2])$ – month (01‑12). ^((0?[1-9])|([12][0-9])|30|31)$ – day of month (01‑31).

Money formats: ^[1-9][0-9]*$ – non‑zero integer. ^(0|[1-9][0-9]*)$ – zero or non‑zero integer. ^(0|-?[1-9][0-9]*)$ – optional leading minus. ^[0-9]+(\.[0-9]+)?$ – integer or decimal. ^[0-9]+(\.[0-9]{2})?$ – optional two‑decimal‑place fraction. ^[0-9]+(\.[0-9]{1,2})?$ – optional 1‑2 decimal places. ^[0-9]{1,3}(,[0-9]{3})*(\.[0-9]{1,2})?$ – commas as thousand separators. ^([0-9]+|[0-9]{1,3}(,[0-9]{3})*)(\.[0-9]{1,2})?$ – flexible comma placement. ^([a-zA-Z]+-?)+[a-zA-Z0-9]+\.[xX][mM][lL]$ – XML file name. [一-龥] – single Chinese character. [^-ÿ] – double‑byte character (including Chinese). \s* – blank lines (useful for removal). <(\S*?)[^>]*>.*?</\1>|<.*? /> – simple HTML tag matcher. ^\s*|\s*$ – leading/trailing whitespace. [1-9][0-9]{4,} – QQ number (minimum 10000). [1-9]\d{5}(?!\d) – Chinese postal code. \d+\.\d+\.\d+\.\d+ – basic IP address pattern.

((?:(?:25[0-5]|2[0-4]\d|[01]?\d?\d)\.){3}(?:25[0-5]|2[0-4]\d|[01]?\d?\d))

– precise IPv4 matcher.