Accumulate regular expressions that are more commonly used (for example, matching Chinese, matching html) _ Regular expressions

Source: Internet
Author: User
Tags lowercase pow

Regular Expressions (Regular Expression, often abbreviated as regex, RegExp, or re) in code are a concept of computer science. A regular expression uses a single string to describe and match a series of strings that conform to a certain syntactic rule. In many text editors, regular expressions are often used to retrieve and replace text that conforms to a pattern. Many programming languages support the use of regular expressions for string manipulation. In many text editors, regular expressions are often used to retrieve and replace text that conforms to a pattern.

Matching regular expressions for Chinese characters: [U4E00-U9FA5]

Commentary: Matching Chinese is really a headache, with this expression will be easy to do
Match Double-byte characters (including Chinese characters): [^x00-xff]
Commentary: can be used to compute the length of a string (a double-byte character length meter 2,ascii 1 characters)
A regular expression that matches a blank row: ns*r
Commentary: can be used to delete blank lines
Regular expression:< matching HTML tags (s*?) [^>]*>.*?| <.*? />
Commentary: The online version is too bad, the above can only match the part of the complex nested tags still powerless
A regular expression that matches the end-end whitespace character: ^s*|s*$
Commentary: A useful expression that can be used to delete white-space characters (including spaces, tabs, page breaks, and so on) at the end of a line at the beginning
Regular expression matching an email address: w+ ([-+.] w+) *@w+ ([-.] w+) *.w+ ([-.] w+) *
Commentary: Form validation is useful
Regular expressions that match URL URLs: [a-za-z]+://[^s]*
Commentary: Online circulation of the version of the function is very limited, which can meet the basic requirements
Match account number is legal (beginning of letter, allow 5-16 bytes, allow alphanumeric underline): ^[a-za-z][a-za-z0-9_]{4,15}$
Commentary: Form validation is useful
Match domestic phone number: D{3}-d{8}|d{4}-d{7}
Commentary: Match form such as 0511-4405222 or 021-87888822
Matching Tencent QQ Number: [1-9][0-9]{4,}
Commentary: Tencent QQ number starting from 10000
Match China ZIP Code: [1-9]d{5} (?! D
Commentary: China postal code is 6 digits
Matching ID: d{15}|d{18}
Commentary: China's ID card is 15-or 18-digit
Matching IP address: d+.d+.d+.d+
Commentary: Useful when extracting IP addresses
Match a specific number:
^[1-9]d*$//Matching positive integer
^-[1-9]d*$//matching negative integers
^-? [1-9]d*$//matching integer
^[1-9]d*|0$//matching nonnegative integer (positive integer + 0)
^-[1-9]d*|0$//matching non positive integer (negative integer + 0)
^[1-9]d*.d*|0.d*[1-9]d*$//matching positive floating-point numbers
^-([1-9]d*.d*|0.d*[1-9]d*) $//matching negative floating-point number
^-? ([1-9]d*.d*|0.d*[1-9]d*|0?. 0+|0) $//matching floating-point number
^[1-9]d*.d*|0.d*[1-9]d*|0? 0+|0$//matching nonnegative floating-point number (positive floating-point number + 0)
^ (-([1-9]d*.d*|0.d*[1-9]d*)) |? 0+|0$//matching non-positive floating-point numbers (negative floating-point number + 0)
Commentary: useful when dealing with large amounts of data, pay attention to corrections when applied
Match a specific string:
^[a-za-z]+$//Match a string of 26 English letters
^[a-z]+$//Match a string of 26 uppercase letters
^[a-z]+$//Match string consisting of 26 lowercase letters
^[a-za-z0-9]+$//Match a string of numbers and 26 English letters
^w+$//Match A string of numbers, 26 English letters, or underscores
The validation features and their validation expressions when using the RegularExpressionValidator validation control are described below:
Only numbers can be entered: "^[0-9]*$"
Only n digits can be entered: "^d{n}$"
You can enter at least n digits: "^d{n,}$"
Only m-n digits can be entered: "^d{m,n}$"
Only numbers beginning with 0 and not 0 can be entered: ^ (0|[ 1-9][0-9]*) $ "
You can only enter positive real numbers with two decimal digits: ^[0-9]+ (. [ 0-9]{2})? $ "
You can only enter positive real numbers with 1-3 decimal digits: ^[0-9]+ (. [ 0-9]{1,3})? $ "
You can only enter a Non-zero positive integer: "^+?" [1-9] [0-9]*$]
You can only enter a Non-zero negative integer: "^-[1-9][0-9]*$"
You can only enter characters with a length of 3: "^. {3}$ "
You can only enter a string of 26 English letters: "^[a-za-z]+$"
You can only enter a string of 26 uppercase English letters: "^[a-z]+$"
You can only enter a string consisting of 26 lowercase English letters: "^[a-z]+$"
You can only enter a string of numbers and 26 English letters: "^[a-za-z0-9]+$"
You can only enter a string of numbers, 26 English letters, or underscores: "^w+$"
Verify user password: "^[a-za-z]w{5,17}$" in the correct format: Beginning with the letter, length between 6-18,
Only characters, numbers, and underscores can be included.
Verify that there are ^%& ',; =?$ ' characters: "[^%&",; = $x 22]+ "
Only Chinese characters can be entered: "^[u4e00-u9fa5],{0,}$"
Verify email Address: "^w+[-+." w+) *@w+ ([-.] w+) *.w+ ([-.] w+) *$ "
Verify InternetURL: "^http://([w-]+.) +[w-]+ (/[w-./?%&=]*)? $ "
Verify phone Number: "^ ((d{3,4}) |d{3,4}-)? d{7,8}$"
The correct format is: "Xxxx-xxxxxxx", "xxxx-xxxxxxxx", "xxx-xxxxxxx",
"Xxx-xxxxxxxx", "XXXXXXX", "XXXXXXXX".
Verify ID Number (15-bit or 18-digit): "^d{15}|d{}18$"
Verify 12 months of the year: "^" (0?[ 1-9]|1[0-2]) $ "The correct format is:" 01 "-" 09 "and" 1 "" 12 "
Verify one months of 31 days: "^ (0?[ 1-9]) | ((1|2) [0-9]) |30|31) $ "
The correct format is: "01" "09" and "1" "31".
Matching regular expressions for Chinese characters: [U4E00-U9FA5]
Match Double-byte characters (including Chinese characters): [^x00-xff]
A regular expression that matches a blank row: n[s|] *r
Regular expression matching HTML tags:/< (. *) >.*|< (. *)/>/
Matching a regular expression with a trailing space: (^s*) | (s*$)
Regular expression matching an email address: w+ ([-+.] w+) *@w+ ([-.] w+) *.w+ ([-.] w+) *
A regular expression that matches URL URLs: http://([w-]+.) +[w-]+ (/[w-/?%&=]*)?

  (1) Application: Computes the length of the string (a double-byte character length meter 2,ascii character count 1)

String.prototype.len=function () {return This.replace ([^x00-xff]/g, "AA"). Length;}

  (2) Application: JavaScript does not have a trim function like VBScript, we can use this expression to implement

String.prototype.trim = function () 
{return 
this.replace (^s*) | ( s*$)/g, ""); 
 

  (3) Application: The use of regular expressions to decompose and transform IP addresses

The function ip2v (IP)//IP address is converted to the corresponding value 
{ 
re=/(d+). d+). (d+). (d+)/g//matching the regular expression of an IP address 
if (re.test (IP)) 
{return 
Regexp.$1*math.pow (255,3)) +regexp.$2*math.pow (255,2  ) +regexp.$3*255+regexp.$4*1 
} 
else 
{ 
throw new Error ("not a valid IP address!") 
} 

  (4) Application: JavaScript program to extract filename from URL address

S= "http://www.9499.net/page1.htm";
S=s.replace (/. * *) {0,} ([^.] +). */ig, "$");//page1.htm

  (5) Application: Using regular expressions to restrict the input of text boxes in Web Forms

Only Chinese can be entered with regular expression restrictions: onkeyup= "Value=value.replace (/[^u4e00-u9fa5]/g,")

"Onbeforepaste=" clipboarddata.setdata (' text ', Clipboarddata.getdata (' text '). Replace (/[^u4e00-u9fa5]/g, ') "

Only full-width characters can be entered with regular expression restrictions: onkeyup= "Value=value.replace (/[^uff00-uffff]/g,")

"Onbeforepaste=" clipboarddata.setdata (' text ', Clipboarddata.getdata (' text '). Replace (/[^uff00-uffff]/g, ') "

Only numbers can be entered with regular expression restrictions: onkeyup= "Value=value.replace (/[^d]/g,") onbeforepaste=
"Clipboarddata.setdata" (' Text ', Clipboarddata.getdata (' text '). Replace (/[^d]/g, ') "

Only numbers and English can be entered with regular expression restrictions: onkeyup= "Value=value.replace (/[w]/g,")

"Onbeforepaste=" clipboarddata.setdata (' text ', Clipboarddata.getdata (' text '). Replace (/[^d]/g, "

The above content is the entire narration of this article, hope everybody likes, if everybody has the better knowledge about regular expression, can share Oh.

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.