Summary and sharing of commonly used regular expressions in C#

This article mainly introduces the commonly used http://www.php.cn/wiki/1548.html" target="_blank">regular expressions in #Expression. It has certain reference value. Let’s take a look at it with the editor.

The following are some regular expressions we have written. You can go online first. Evaluate it.

1. Expression of check digits

1 Number: ^[0-9]*$

2 n-digit Number: ^\d{n}$

3 Number with at least n digits: ^\d{n,}$

4 Number with m-n digits: ^\d{m,n} $

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

6 Numbers starting with non-zero with up to two decimal places Number: ^([1-9][0-9]*)+(.[0-9]{1,2})?$

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

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

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

10 has 1 ~Positive real number with 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-negative floating point number: ^\d+(\.\d+)?$ or ^[1-9]\d*\.\d*|0\.\d* [1-9]\d*|0?\.0+|0$

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

17 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]*))$

18 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]*))) $

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

2. Expression of check characters

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

2 English and numbers: ^[A-Za-z0-9]+$ or ^[A-Za-z0-9]{4,40 }$

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

4 A string consisting of 26 English letters: ^ [A-Za-z]+$

5 A string consisting of 26 uppercase English letters: ^[A-Z]+$

6 A string consisting of 26 lowercase English letters :^[a-z]+$

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

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

9 Chinese, English, and 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 containing ^%&',;=?$\": [^%&',;=?$\x22]+

12 It is forbidden to enter characters containing ~: [^~\x22]+

3. Special requirements expression

1 EmailAddress: ^\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 phone 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 digits, 18 digits): ^\d{15}|\d{18}$

8 Short ID number (numbers, letters ending in x): ^([0-9]){7,18}(x|X)?$ or ^\d{8,18}|[0-9x]{8 ,18}|[0-9X]{8,18}?$

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

10 Password (starting with a letter, length between 6 and 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, special characters cannot be used, the length is between 8-10 time): ^(?=.*\d)(?=.*[a-z])(?=.*[A-Z]).{8,10}$

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

13 12 months of the 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 Money input format:

16 (1). There are four money representation forms we can accept: "10000.00" and "10,000.00", and "10000" and "10,000" without "cent": ^[1-9][0-9]*$

17 (2). This means any number that does not start with 0, but it also means that a character "0" does not pass, so we use 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 does not start with 0. Let the user start with 0. Remove the negative sign too, Because money can't be negative. What we need to add below is the possible decimal 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). In this way, we stipulate that there must be two decimal places after the decimal point. If you think it is too harsh, you can do this: ^[0-9]+(.[0-9 ]{1,2})?$

22 (7). This allows the user to write only one decimal place. Now we should consider the commas in the numbers. We can do this: ^[0-9] {1,3}(,[0-9]{3})*(.[0-9]{1,2})?$

23 (8).1 to 3 numbers, followed by Follow any number of commas + 3 digits, and the commas become 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 an empty string is also ok If you accept it (strange, why?) Finally, don’t forget to remove the backslash when using the function. Common mistakes are 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 the string (The length of a double-byte character counts as 2, and the ASCII character counts as 1))

28 Regular expression for blank lines: \n\s*\r (can be used todeleteblank lines )

29 Regular expression for HTML tags: <(\S*?)[^>]*>.*?|<.*? /> ( The version circulating on the Internet is too bad. The above one is only partially effective and is still powerless for complex nested tags.)

30 Regular expression for leading and trailing whitespace characters: ^\s*|\s*$ or (^ \s*)|(\s*$) (can be used to delete whitespace characters at the beginning and end of the line (including spaces, tabs, form feeds, etc.), a very useful expression)

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)

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