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I would like to share with you what regular expressions are commonly used. I believe most people don't know much about them, so share this article for your reference. I hope you will learn a lot after reading this article. Let's learn about it together.

I. the expression of the check number

Number: ^ [0-9] * $

N-digit number: ^\ d {n} $

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

The number of mmurn digits: ^\ d {mrecom n} $

Zero and non-zero numbers: ^ (0 | [1-9] [0-9] *) $

A number with up to two decimal places at the beginning of a non-zero: ^ ([1-9] [0-9] *) + (. [0-9] {1J2})? $

Positive or negative numbers with 1-2 decimal places: ^ (\ -)?\ d + (\. D {1jin2})? $

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

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

A positive real number with 1 to 3 decimal places: ^ [0-9] + (. [0-9] {1jue 3})? $

Non-zero positive integers: ^ [1-9]\ During $or ^ ([1-9] [0-9] *) {1 ~ (st) 3} $or ^\ +? [1-9] [0-9] * $

Non-zero negative integers: ^\-[1-9] [] 0-9 "* $or ^-[1-9]\ dflowers $

Non-negative integer: ^\ dBy $or ^ [1-9]\ d* | 0 $

Non-positive integer: ^-[1-9]\ d* | 0$ or ^ ((-\ d+) | (0 +)) $

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

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

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

Second, the expression of check characters

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

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

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

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

A string of 26 uppercase letters: ^ [Amurz] + $

A string of 26 lowercase letters: ^ [amurz] + $

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

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

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

Chinese, English, numbers but excluding underscores and other symbols: ^ [\ u4E00 -\ u9FA5A-Za-z0-9] + $or ^ [\ u4E00 -\ u9FA5A-Za-z0-9] {2jue 20} $

You can enter characters such as ^% &',; =? $\ ": [^% &',; =? $\ x22] +

Prohibited from entering characters containing ~: [^ ~\ x22] +

III. Expression of special requirements

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

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

InternetURL: [a-zA-z] +: / / [^\ s] * or ^ http://([\w-]+\.)+[\w-]+(/[\w-./?%&=]*)?$

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} $

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

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

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

Short ID card number (ending with number and letter x): ^ ([0-9]) {7jue 18} (x | X)? $or ^\ d {8jue 18} | [0-9x] {8jurisdiction 18} | [0-9X] {8jue 18}? $

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

Password (begins with a letter, is between 6 and 18 in length, and can only contain letters, numbers and underscores): ^ [a-zA-Z]\ w {5Magne17} $

Strong password (must contain a combination of uppercase and lowercase letters and numbers, cannot use special characters, length is between 8 and 10): ^ (? =. *\ d) (? =. * [Amurz]) (? =. * [Amurz]). {8jue 10} $

Date format: ^\ d {4} -\ d {1pc2} -\ d {1pc2}

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

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

The input format of the money:

There are four forms of money we can accept: "10000.00" and "10000.00", and "10000" and "10000" without "points": ^ [1-9] [0-9] * $

This means any number that does not start with 0, but it also means that a character "0" does not pass, so we take the following form: ^ (0 | [1-9] [0-9] *) $

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] *) $

This represents a 0 or a number that may be negative and begins with a non-zero. Let the user start with 0. Get rid of the negative sign, too, because the money can't be negative. What we want to add next is the possible decimal part: ^ [0-9] + (. [0-9] +)? $

It must be noted that there should be at least 1 digit after the decimal point, so "10." No, but "10" and "10.2" are passed: ^ [0-9] + (. [0-9] {2})? $

In this way, we stipulate that there must be two digits after the decimal point. If you think it is too harsh, you can go like this: ^ [0-9] + (. [0-9] {1mem2})? $

This allows the user to write only one decimal place. Now it's time for us to consider the comma in the number. We can go like this: ^ [0-9] {1 # 3} (, [0-9] {3}) * (. [0-9] {1 # 2})? $

1 to 3 digits, followed by any comma + 3 digits, comma becomes optional instead of having to: ^ ([0-9] + | [0-9] {1magin 3} (, [0-9] {3}) *) (. [0-9] {1pr 2})? $

Note: this is the end result. Don't forget that "+" can be replaced by "*". If you think empty strings are acceptable (strange, why?) Finally, don't forget to remove the backslash when using the function. The usual mistakes are here.

Xml file: ^ ([a-zA-Z] + -?) + [a-zA-Z0-9] +\. [X | X] [m | M] [l | L] $

Regular expressions for Chinese characters: [\ u4e00 -\ u9fa5]

Double-byte characters: [^\ X00 -\ xff] (including Chinese characters, can be used to calculate the length of a string (a double-byte character length meter 2)

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

Regular expression of HTML tags:] * >. *? | (the version circulated on the Internet is too bad, the above one is only partial, and there is nothing I can do about complex nested tags.)

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

Tencent QQ number: [1-9] [0-9] {4,} (Tencent QQ number starts from 10000)

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

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

IP address: (?: (?) 25 [0-5] | 2 [0-4]\ d | [01]?\\ d?\\ d)\\ d) {3} (?: 25 [0-5] | 2 [0-4]\\ d | [01]?\\ d?\\ d)) (provided by @ Fei long San Shao, thank you for sharing)

The above is all the content of the article "what are the Common regular expressions?" Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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