Regular

Many friends who don’t understand regular rules often search the Internet for a long time when they need to use regular check data, but the results they find still do not meet the requirements. So I recently sorted out some regular expressions commonly used in development and shared them here. Keep it for yourself and as a reference for your friends.
Expression of check digit
1 Digit: ^[0-9]*$
2 Digit of n digits: ^\d{n}$
3 Digit of at least n digits: ^\d{n,}$
Digit of 4 mn digits : ^\d{m,n}$
5 Zero and non-zero leading numbers: ^(0|[1-9][0-9]*)$
6 Non-zero leading numbers with up to two decimal places: ^ ([1-9][0-9]*)+(.[0-9]{1,2})?$
7 Positive or negative number with 1-2 decimal places: ^(\-)?\d+ (\.\d{1,2})?$
8 Positive, negative, and decimal numbers: ^(\-|\+)?\d+(\.\d+)?$
9 Positive real numbers with two decimal places: ^[0-9]+(.[0-9]{2})?$
10 Positive real numbers with 1~3 decimal places: ^[0-9]+(.[0-9]{1,3} )?$
11 Non-zero positive integer: ^[1-9]\d*$ or ^([1-9][0-9]*){1,3}$ or ^\+?[1-9 ][0-9]*$
12 Non-zero negative integer: ^\-[1-9][]0-9"*$ or ^-[1-9]\d*$
13 Non-negative integer: ^\ d+$ or ^[1-9]\d*|0$
14 non-positive integer: ^-[1-9]\d*|0$ or ^((-\d+)|(0+))$
15 non- positive Negative float: ^\d+(\.\d+)?$ or ^[1-9]\d*\.\d*|0\.\d*[1-9]\d*|0?\. 0+|0$
16 Non-positive floating-point numbers: ^((-\d+(\.\d+)?)|(0+(\.0+)?))$ or ^(-([1-9]\d*\.\ d*|0\.\d*[1-9]\d*))|0?\.0+|0$
17 Positive float: ^[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]*))$
18 Negative float: ^ -([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]*)))$
19 Floating point: ^(-?\d+)(\.\d+)?$ or ^-?([1-9]\d*\.\ d*|0\.\d*[1-9]\d*|0?\.0+|0)$
Check character expression
1 Chinese character: ^[\u4e00-\u9fa5]{0,}$
2 English and numbers: ^[A-Za-z0-9]+$ or ^[A-Za-z0-9]{4,40}$
3 All characters of length 3-20: ^.{3,20 }$
4 A string consisting of 26 English letters: ^[A-Za-z]+$
5 A string consisting of 26 uppercase English letters: ^[AZ]+$
6 A string consisting of 26 lowercase English letters String: ^[az]+$
7 String consisting of numbers and 26 English letters: ^[A-Za-z0-9]+$
8 String consisting of numbers, 26 English letters or underscores: ^ \w+$ or ^\w{3,20}$
9 Chinese, English, numbers including underscores: ^[\u4E00-\u9FA5A-Za-z0-9_]+$
10 Chinese, English, numbers but not including underscores and other symbols: ^[\u4E00-\u9FA5A-Za-z0- 9]+$ or ^[\u4E00-\u9FA5A-Za-z0-9]{2,20}$
11 You can enter characters including ^%&',;=?$\": [^%&',; =?$\x22]+
12 Characters containing ~ are prohibited: [^~\x22]+
Special demand expression
1 Email address: ^\w+([-+.]\w+)*@\w+([-. ]\w+)*\.\w+([-.]\w+)*$
2 Domain name: [a-zA-Z0-9][-a-zA-Z0-9]{0,62}(/.[ a-zA-Z0-9][-a-zA-Z0-9]{0,62})+/.?
3 InternetURL: <[a-zA-z]+://[^\s]* or ^http://([\w-]+\.)+[\w-]+(/[\w-./?%&=]*)?$<
4 Mobile number: ^(13[0- 9]|14[5|7]|15[0|1|2|3|5|6|7|8|9]|18[0|1|2|3|5|6|7|8|9 ])\d{8}$
5 Phone numbers ("XXX-XXXXXXX", "XXXX-XXXXXXXX", "XXX-XXXXXXX", "XXX-XXXXXXXX", "XXXXXXX" and "XXXXXXXX"): ^(\(\d {3,4}-)|\d{3.4}-)?\d{7, 8}$
6 Domestic phone number (0511-4405222, 021-87888822): \d{3}-\d{8}|\d{4}-\d{7}
7 ID number (15-digit, 18-digit number): ^\d{15}|\d{18}$
8 Short ID number (number, letter x ending): ^([0-9]){7,18}(x|X)?$ or ^\d{8,18}|[0-9x]{8 ,18}|[0-9X]{8,18}?$
9 Is the account number legal (begins with a letter, allows 5-16 bytes, and allows alphanumeric underscores): ^[a-zA-Z][a-zA- Z0-9_]{4,15}$
10 Password (starting with a letter, length between 6~18, can only contain letters, numbers and underscores): ^[a-zA-Z]\w{5,17} $
11 Strong password (must contain a combination of uppercase and lowercase letters and numbers, no special characters, length between 8-10): ^(?=.*\d)(?=.*[az])(?= .*[AZ]).{8,10}$  
12 Date format: ^\d{4}-\d{1,2}-\d{1,2}
13 12 months of a year (01～09 and 1~12): ^(0?[1-9]|1[0-2])$
14 31 days of a month (01~09 and 1~31): ^((0?[1-9] )|((1|2)[0-9])|30|31)$ 
15 Input format of money:
16 1. There are four representations of money we can accept: "10000.00" and "10,000.00", and no "10000" and "10,000" for "cents": ^[1-9][0-9]*$ 
17 2. This means any number that does not start with 0, however, it also means a character "0" does not pass, so we take the following form: ^(0|[1-9][0-9]*)$ 
18 3. A 0 or a number that does not start with 0. We can also allow a negative sign at the beginning :^(0|-?[1-9][0-9]*)$ 
19 4. This means a 0 or a number that may be negative and not 0 at the beginning. Let the user start with 0. Also remove the negative sign, because money cannot always be negative. What we want to add next is Explain the possible fractional part: ^[0-9]+(.[0-9]+)?$ 
20 5. It must be noted that there should be at least 1 digit after the decimal point, so "10." is not passed , but "10" and "10.2" are passed: ^[0-9]+(.[0-9]{2})?$ 
21 6. This way we stipulate that there must be two digits after the decimal point, if you think too much Harsh, it can be like this: ^[0-9]+(.[0-9]{1,2})?$ 
22 7. This allows the user to write only one decimal place. Now we should consider the comma in the number , we can do this: ^[0-9]{1,3}(,[0-9]{3})*(.[0-9]{1,2})?$ 
23 8.1 to 3 numbers, Followed by any comma + 3 digits, the comma becomes optional, not required: ^([0-9]+|[0-9]{1,3}(,[0-9]{3})* )(.[0-9]{1,2})?$ 
24 Note: This is the final result, don't forget that "+" can be replaced with "*" if you think empty strings are acceptable (strange, Why?) Finally, don't forget to remove the backslash when using the function, the general error is here
25 xml file: ^([a-zA-Z]+-?)+[a-zA-Z0- 9]+\\.[x|X][m|M][l|L]$
26 Regular expression for Chinese characters: [\u4e00-\u9fa5]27 Double-byte characters: [^\x00-\xff ] (including Chinese characters, can be used to calculate the length of a string (a double-byte character counts as 2, ASCII character counts as 1))
28 Regular expression for blank lines: \n\s*\r (can be used to delete blank lines)
29 Regular expressions for HTML tags: <(\S*?)[^>]*>.*?<!--\1-->|<.*? /> (The version circulating on the Internet is too bad, the above one It can only partially, and still can't do anything about complex nested tags)
30 regular expressions for leading and trailing whitespace characters: ^\s*|\s*$ or (^\s*)|(\s*$) (can be used to Delete the blank characters at the beginning and end of the line (including spaces, tabs, form feeds, etc.), very useful expressions)
31 Tencent QQ number: [1-9][0-9]{4,} (Tencent QQ number starts from 10000)
32 China Postal Code: [1-9]\d{5}(?!\d) (China Postal Code is 6 digits)
33 IP Address: \d+\.\d+\.\d+ \.\d+ (useful when extracting IP address)
34 IP address: ((?:(?:25[0-5]|2[0-4]\\d|[01]?\\d?\\d )\\.){3}(?:25[0-5]|2[0-4]\\d|[01]?\\d?\\d))