Essential Regular Expressions for Data Validation in Development

Many developers struggle to find reliable regular expressions for data validation; this collection gathers frequently used patterns for numbers, characters, and special requirements, serving as a quick reference.

Numeric Validation Expressions

^[0-9]*$

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

Character Validation Expressions

^[一-龥]{0,}$

– Chinese characters ^[A-Za-z0-9]+$ – alphanumeric ^.{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+$ – letters, digits, underscore ^[一-龥A-Za-z0-9_]+$ – Chinese, letters, digits, underscore ^[一-龥A-Za-z0-9]+$ – Chinese, letters, digits (no underscore) [^%&',;=?$"]+ – allows special symbols like ^%&',;=?$" [^~"]+ – disallows tilde (~)

Special‑Requirement Expressions

^\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]* – generic URL ^(13[0-9]|14[57]|15[0-35-9]|18[0-9])\d{8}$ – Chinese mobile number ^(\d{3,4}-)?\d{7,8}$ – telephone number ^\d{3}-\d{8}|\d{4}-\d{7}$ – domestic telephone formats ^\d{15}|\d{18}$ – ID card number ^[0-9]{7,18}(x|X)?$ – short ID with optional X ^[a-zA-Z][a-zA-Z0-9_]{4,15}$ – valid account name ^[a-zA-Z]\w{5,17}$ – password starting with a letter, 6‑18 chars ^(?=.*\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) ^[1-9][0-9]*$ – monetary amount without leading zero ^(0|[1-9][0-9]*)$ – zero or non‑zero amount ^(0|-?[1-9][0-9]*)$ – optional negative amount ^[0-9]+(\.[0-9]+)?$ – amount with optional decimal ^[0-9]+(\.[0-9]{2})?$ – amount with exactly two decimal places ^[0-9]+(\.[0-9]{1,2})?$ – amount with 1‑2 decimal places ^[0-9]{1,3}(,[0-9]{3})*(\.[0-9]{1,2})?$ – amount with commas and optional decimals ^([0-9]+|[0-9]{1,3}(,[0-9]{3})*)(\.[0-9]{1,2})?$ – flexible comma‑separated amount ^([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 line (useful for removal) <(\S*?)[^>]*>.*?</\1>|<.*? /> – simple HTML tag matcher ^\s*|\s*$ – trim leading/trailing whitespace [1-9][0-9]{4,} – Tencent QQ number (minimum 10000) [1-9]\d{5}(?!\d) – Chinese postal code (6 digits) \d+\.\d+\.\d+\.\d+ – 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