A collection of commonly used regular expressions (numbers, characters, fixed formats)

Regular expression (regular expression) describes a string matching pattern, which can be used to check whether a string contains a certain substring, replace the matching substring, or extract from a string that meets a certain condition. substrings, etc.

When listing directories, *.txt in dir *.txt or ls *.txt is not a regular expression, because the meaning of * here is different from the * in regular expressions.

The method of constructing a regular expression is the same as that of creating a mathematical expression. That is, small expressions can be combined together to create larger expressions using a variety of metacharacters and operators. The components of a regular expression can be a single character, a collection of characters, a range of characters, a selection between characters, or any combination of all of these components.

Regular expressions are text patterns composed of ordinary characters (such as the characters a through z) and special characters (called "metacharacters"). A pattern describes one or more strings to match when searching for text. A regular expression acts as a template that matches a character pattern with a searched string.

The following is the editor's daily collection of some regular expressions commonly used in work. Commonly used regular verification expressions:

Number-related regular expressions

Number: ^ [0-9]*$

n-digit fixed-length number: ^\d{n}$

m-n-digit number: ^\d{ m,n}$

Numbers starting with zero and non-zero: ^(0|[1-9][0-9]*)$

non-zero The number with up to two decimal places at the beginning: ^([1-9][0-9]*)+(.[0-9]{1,2})?$

with Positive or negative numbers with 1-2 decimal places: ^(\-)?\d+(\.\d{1,2})?$

Positive numbers, negative numbers, and decimals: ^ (\-|\+)?\d+(\.\d+)?$

Positive real number with two decimal places: ^[0-9]+(.[0-9]{ 2})?$

Positive real numbers with 1 to 3 decimal places: ^[0-9]+(.[0-9]{1,3})?$

Positive integer: ^\d+$ or ^[1-9]\d*|0$

Negative integer: ^-[1-9]\d*|0$ Or ^((-\d+)|(0+))$

Positive floating point number: ^[1-9]\d*\.\d*|0\.\d*[ 1-9]\d*$ or ^(([0-9]+\.[0-9]*[1-9][0-9]*)|([0-9]*[1-9 ][0-9]*\.[0-9]+)|([0-9]*[1-9][0-9]*))$

Negative floating point number :^-([1-9]\d*\.\d*|0\.\d*[1-9]\d*)$ or ^(-(([0-9]+\.[0 -9]*[1-9][0-9]*)|([0-9]*[1-9][0-9]*\.[0-9]+)|([0-9 ]*[1-9][0-9]*)))$

Floating point number: ^(-?\d+)(\.\d+)?$ or ^-?([ 1-9]\d*\.\d*|0\.\d*[1-9]\d*|0?\.0+|0)$

Regular expressions related to characters

Chinese characters: ^[\u4e00-\u9fa5]{0,}$

All characters with a length of 3-20: ^.{3,20}$

A string composed of numbers and 26 English letters: ^[A-Za-z0-9]+$

A string composed of numbers, 26 English letters or underscores String: ^\w+$ or ^\w{3,20}$

Chinese, English, numbers including underline: ^[\u4E00-\u9FA5A-Za-z0-9_]+$

Chinese, English, numbers but not including underscores and other symbols: ^[\u4E00-\u9FA5A-Za-z0-9]+$ or ^[\u4E00-\u9FA5A-Za-z0- 9]{2,20}$

Whether the account is legal (starting with a letter, 5-16 bytes allowed, alphanumeric underscores allowed): ^[a-zA-Z][a-zA- Z0-9_]{4,15}$

Password (starts with a letter, is between 6 and 18 in length, can only contain letters, numbers and underscores): ^[a-zA-Z ]\w{5,17}$

Strong password (must contain a combination of uppercase and lowercase letters and numbers, no special characters, length between 8-10): ^(?=. *\d)(?=.*[a-z])(?=.*[A-Z]).{8,10}$

Fixed format conventional regular expression

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

Website Domain name: [a-zA-Z0-9][-a-zA-Z0-9]{0,62}(/.[a-zA-Z0-9][-a-zA-Z0-9]{0 ,62})+/.?

URL: ^http://([\w-]+\.)+[\w-]+(/[\w-./ ?%&=]*)?$

Mobile phone number: ^(13[0-9]|17[0-9]|14[5|7]|15[0|1| 2|3|5|6|7|8|9]|18[0|1|2|3|5|6|7|8|9])\d{8}$

Phone number("XXX-XXXXXXX", "XXXX-XXXXXXXX", "XXX-XXXXXXX", "XXX-XXXXXXXX", "XXXXXXX" and "XXXXXXXX): ^(\(\d{3,4}-)| \d{3.4}-)?\d{7,8}$

Domestic phone number (0511-4405222, 021-87888822): \d{3}-\d{8}| \d{4}-\d{7}

ID card number (15 digits, 18 digits): ^\d{15}|\d{18}$

Date format: ^\d{4}-\d{1,2}-\d{1,2}

12 months of the year (01～09 and 1 ~12):^(0?[1-9]|1[0-2])$

31 days of a month (01~09 and 1~31):^((0 ?[1-9])|((1|2)[0-9])|30|31)$

Tencent QQ number: [1-9][0-9]{ 4,8} (Tencent QQ number starts from 10000, currently the longest is 10 digits)

China Postal Code: [1-9]\d{5}(?!\d) (China Postal code is 6 digits)

IP address:\d+\.\d+\.\d+\.\d+ (useful when extracting IP address)

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

The above is a collection of commonly used regular expressions introduced by the editor. (Numbers, characters, fixed formats), hope it helps everyone!

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