Detailed explanation of the most commonly used regular expressions in PHP

This article will organize and introduce the most commonly used regular expressions in PHP. It has a very good reference value. Let’s take a look at it with the editor.

1. Expression of check numbers

Number: ^[0-9] *$

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

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

m-n-digit number ：^\d{m,n}$

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

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

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

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

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

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

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

Not Negative integer of zero: ^\-[1-9][]0-9″*$ or ^-[1-9]\d*$

Non-negative integer: ^\d+$ 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]\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)$

2. Expression of check characters

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

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

The length is 3-20 All characters: ^.{3,20}$

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

consists of 26 uppercase English letters String: ^[A-Z]+$

String consisting of 26 lowercase English letters: ^[a-z]+$

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

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

Chinese, English, numbers including underscores: ^[\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}$

can be entered containing ^%&',;=?$ \" and other characters: [^%&',;=?$\x22]+

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

3. Special requirement expression

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

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

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{3,4}-)|\d{3.4}-)?\d{7,8}$

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

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

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

Is the account 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, has a length between 6 and 18, and 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, special characters cannot be used, and the length is between 8-10): ^(?=.*\d)(?=.*[a-z])(?=.*[A-Z]).{8,10}$

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)$

Input format of money:

• There are four forms of money representation we can accept: "10000.00" and “10,000.00″, and “10000″ and “10,000″ without “cent”: ^[1-9][0-9]*$

• This means any one does not start with 0 number at the beginning, however, this also means that a character "0" is not passed, so we use 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 means a 0 or a number that may be negative and does not start with 0. Let the user start with 0. Also remove the negative sign, because money can never be negative. Next we will What is added is to indicate the possible decimal part: ^[0-9]+(.[0-9]+)?$

• It must be noted that there should be at least 1 after the decimal point digits, so "10." is not passed, but "10" and "10.2" are passed: ^[0-9]+(.[0-9]{2})?$

• 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})?$

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

• 1 to 3 numbers, followed by any number of commas + 3 numbers, the commas become optional instead of required: ^([0-9]+|[0 -9]{1,3}(,[0-9]{3})*)(.[0-9]{1,2})?$

• Remarks: 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. Common mistakes are here

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

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

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 is counted as 2, and the ASCII character is counted as 1))

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

HTML Marked regular expression: ]*>.*?\1>|<.> (The version circulating on the Internet is too bad, the one above It can only partially work, and it still can’t do anything about complex nested tags)

Regular expression of leading and trailing whitespace characters: ^\s*|\s*$ or (^\s*)|(\s*$ ) (can be used to delete blank characters at the beginning and end of the line (including spaces, tabs, form feeds, etc.), 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+\.\d+ (useful when extracting IP address)

The above is the detailed explanation of the most commonly used regular expressions in PHP , for more related content, please pay attention to the PHP Chinese website (www.php.cn)!

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