Summary of common Regular Expressions in C)

Summary of common Regular Expressions in C #

A newbie must pay attention to the manual, which can save a lot of writing.CodeTime, China self-learning Programming Network for new friends to sort out the release.

Only numbers are allowed: "^ [0-9] * $ ".

Only n digits can be entered: "^ \ D {n} $ ".

You can only enter at least N digits: "^ \ D {n,} $ ".

Only M ~ can be input ~ N-digit :. "^ \ D {m, n} $"

Only numbers starting with zero and non-zero can be entered: "^ (0 | [1-9] [0-9] *) $ ".

Only positive numbers with two decimal places can be entered: "^ [0-9] + (. [0-9] {2 })? $ ".

Only 1 ~ Positive number of three decimal places: "^ [0-9] + (. [0-9] {1, 3 })? $ ".

Only a non-zero positive integer can be entered: "^ \ +? [1-9] [0-9] * $ ".

Only a non-zero negative integer can be entered: "^ \-[1-9] [] 0-9" * $.

Only 3 characters can be entered: "^. {3} $ ".

You can only enter a string consisting of 26 English letters: "^ [A-Za-Z] + $ ".

You can only enter a string consisting of 26 uppercase letters: "^ [A-Z] + $ ".

You can only enter a string consisting of 26 lower-case English letters: "^ [A-Z] + $ ".

You can only enter a string consisting of a number and 26 English letters: "^ [A-Za-z0-9] + $ ".

You can only enter a string consisting of digits, 26 English letters, or underscores (_): "^ \ W + $ ".

Verify the User Password: "^ [A-Za-Z] \ W {5, 17} $". The correct format is: start with a letter, with a length of 6 ~ It can only contain characters, numbers, and underscores.

Check whether ^ % & ',; =? $ \ "And other characters:" [^ % & ',; =? $ \ X22] + ".

Only Chinese characters can be entered: "^ [\ u4e00-\ u9fa5] {0,} $"

Verify email address: "^ \ W + ([-+.] \ W +) * @ \ W + ([-.] \ W + )*\. \ W + ([-.] \ W +) * $ ".

Verify interneturl: "^ http: // ([\ W-] + \.) + [\ W-] + (/[\ W -./? % & =] *)? $ ".

Verification phone number: "^ (\ D {3, 4}-) | \ D {3.4 }-)? \ D {7,8} $ "correct format:" XXX-XXXXXXX "," XXXX-XXXXXXXX "," XXX-XXXXXXX "," XXX-XXXXXXXX "," xxxxxxx "and" XXXXXXXX ".

Verify the ID card number (15 or 18 digits): "^ \ D {15} | \ D {18} $ ".

12 months of verification: "^ (0? [1-9] | 1 [0-2]) $ "the correct format is:" 01 "~ "09" and "1 "~ "12 ".

31 days of verification for a month: "^ (0? [1-9]) | (1 | 2) [0-9]) | 30 | 31) $ "the correct format is;" 01 "~ "09" and "1 "~ "31 ".

Use regular expressions to restrict text box input in a webpage form:

You can only enter Chinese characters using regular expressions: onkeyup = "value = value. replace (/[^ \ u4e00-\ u9fa5]/g, '')" onbeforepaste = "clipboardData. setdata ('text', clipboardData. getdata ('text '). replace (/[^ \ u4e00-\ u9fa5]/g ,''))"

You can only enter the full-width characters: onkeyup = "value = value. replace (/[^ \ uff00-\ Uffff]/g, '')" onbeforepaste = "clipboardData. setdata ('text', clipboardData. getdata ('text '). replace (/[^ \ uff00-\ Uffff]/g ,''))"

Use a regular expression to limit that only numbers can be entered: onkeyup = "value = value. replace (/[^ \ D]/g, '')" onbeforepaste = "clipboardData. setdata ('text', clipboardData. getdata ('text '). replace (/[^ \ D]/g ,''))"

You can only enter numbers and English letters using regular expressions: onkeyup = "value = value. replace (/[\ W]/g, '')" onbeforepaste = "clipboardData. setdata ('text', clipboardData. getdata ('text '). replace (/[^ \ D]/g ,''))"

Extract the JavaScript code of the file name from the URL address using a regular expression.Program, The following result is page1

The following is a reference clip: S = "http://www.9499.net/page1.htm" S = S. Replace (/(. * \/) {0,} ([^ \.] +). */ig, "$2 ") Alert (s)

Match double-byte characters (including Chinese characters): [^ \ x00-\ xFF]

Application: Calculate the length of a string (two-byte length Meter 2, ASCII character meter 1)

The following is a reference clip: String. Prototype. Len = function () {return this. Replace ([^ \ x00-\ xFF]/g, "AA"). length ;}

Regular Expression for matching empty rows: \ n [\ s |] * \ r

Regular Expressions matching HTML tags:/<(. *)>. * <\/\ 1> | <(. *) \/>/

Regular Expression matching spaces at the beginning and end: (^ \ s *) | (\ s * $)

The following is a reference clip: String. Prototype. Trim = function () { Return this. Replace (/(^ \ s *) | (\ s * $)/g ,""); }

Use regular expressions to break down and convert IP addresses:

The following is a javascript program that uses regular expressions to match IP addresses and convert IP addresses to corresponding values:

The following is a reference clip: Function ip2v (IP) { Re =/(\ D +) \. (\ D +)/g // Regular Expression matching IP addresses If (Re. Test (IP )) { Return Regexp. $1 * Math. Pow (255) + Regexp. $2 * Math. Pow () + Regexp. $3 * + Regexp. $4*1 } Else { Throw new error ("not a valid IP address! ") } }