Learn regular Expressions (JS, C #) _ Regular expressions

Use of regular expressions in JS

function Myvalid () {
  var errormsg = "";
  var res = true;
  Get the value you want to validate.
  var receivename = $ ("#receiveName"). Val ();//Name
  var receivemobile = $ ("#tMobile"). Val ()/mobile number
  var Validcode = $ ( "#validCode"). Val ()//Verification code

  var regname =/^[\u4e00-\u9fa5]{2,4}$/;//authentication name
  var regmobile =/^1[3|4|5|7|8][0-9]\ d{8}$/;//Verification Mobile phone
  var regcode =/^\d{4}$/;//Authentication Code
  if (!regname.test (Receivename)) {
  errormsg = "name format is incorrect; \n\r ";
  res = false;
  if (!regmobile.test (Receivemobile)) {
  errormsg + = "Cell phone number format is not correct; \n\r";
  res = false;
  if (!regcode.test (Validcode)) {
  errormsg = "Please enter a 4-bit digital authentication code; \n\r";
  res = false;
  if (!res) {
  $.ligerdialog.error (errormsg, error hint);
  }
  return res;
}

Regular expressions in C # use

Using System;
Using System.Collections.Generic;
Using System.Linq;
Using System.Text;

Using System.Threading.Tasks; Namespace regular Expression {using system.text.regularexpressions;//Regular Expression namespace class program {static void Main (string[] ar
       GS) {/* * Regular matching principle: * 1. Only focus on whether there is a string that can be matched without paying attention to its position and other parts that cannot be matched. * 2. Greedy mode: It will match as many as possible, which means it will match to the last string that can be matched. */while (true) {string str = Console.ReadLine ()
        ; The role of the #region meta character _ placeholder//method is to determine whether STR matches a custom regular expression rule//1.
        .: Represents a character placeholder, can represent any one character, must pass in a character, can be Chinese Console.WriteLine (Regex.IsMatch (str, "B.G")); 2. []: Represents a single character of a specified range, you can specify a discontinuous value, or you can specify a contiguous range: 0-9-Z-A-Z legal characters: 0-9-Z-Z-Console.WriteLine (Regex.IsMatch (str, "b[
        0-9]g "));
        In the regular, ^ can only be written at the beginning, if written in the middle, ^ is an ordinary character of the Console.WriteLine (Regex.IsMatch (str, "b[0-9a-z^a-z_]g"));
        Console.WriteLine (Regex.IsMatch (str, "b[^0-9a-za-z_^]g"));
      Here [0-z] contains all the characters between 0-z, and also contains some special symbols  Parsing the order of "b[9-1]g"-[XY] ranges is reversed.
        Can only be in the order of ASCII code from small to large Console.WriteLine (Regex.IsMatch (str, "b[9-1]g"));
        Console.WriteLine (Regex.IsMatch (str, "b[0-9-]g")); 11-19 Console.WriteLine (Regex.IsMatch (str, "[11-19]")); 
        1 1-1 9 Console.WriteLine (Regex.IsMatch (str, "b[^0-9]g")); |: or Console.WriteLine (Regex.IsMatch (str, "[0-9][0-9]|[ 0-9][0-9][0-9])); Hjasdgf1234fjhadsjfhas//If a strict bit number match is involved, you need to add the start ^ and end $: represents a character that must be strictly matched from beginning to end Console.WriteLine (REGEX.ISMATC
        H (str, "^[0-9][0-9]$|^[0-9][0-9][0-9]$"));
        Included in [] is a plain character, not a metacharacters, which, in addition to the ^--need to be followed by the content, if the need to match, you can consider using escape \ Console.WriteLine (Regex.IsMatch (str, @ "^\^$")); 
        Console.WriteLine (Regex.IsMatch (str, "^\\^$")); #endregion #region Meta Character _ modifier//*: It is not a character placeholder, it means that it does not represent a character, it is used to decorate the preceding subexpression appears 0 or more times: The subexpression is the default refers to the character in front, if you need to represent
        Multiple, on the use () contains Console.WriteLine (Regex.IsMatch (str, "ab*g")); Console.WriteLine (Regex.IsMatch (str, "^ (AB) *g$")); +: It is not a character placeholder, it means that it does not represent a character, it is used to modify + the preceding subexpression appears 1 or more times: The subexpression is the default means + the preceding character, if you need to represent multiple, use () contains Console.WriteLine (
        Regex.IsMatch (str, "a+g")); //? : It is not a character placeholder, which means that it does not represent a character, it is used to decorate? The preceding subexpression appears 0 or 1 times: The subexpression is the default. The preceding character, if required, is used () to contain Console.WriteLine (
        Regex.IsMatch (str, "^a?g$")); {N,m}:{n,m} It is not a character placeholder, it means that it does not represent a character, it is used to decorate the preceding subexpression of {n,m} at least n times, up to M Times Console.WriteLine (Regex.IsMatch (str, "^[0-9
        ]{3,4}$ ")); {n}: It is not a character placeholder, stating that it does not represent a character, it is used to decorate the preceding subexpression of {n} only n times Console.WriteLine (Regex.IsMatch (str, "^[1-9][0-9]{17}$|^[
        0-9]{15}$|^[0-9]{17}[xx]$ ")); {N,}: It is not a character placeholder, stating that it does not represent a character, it is used to decorate {n,} The preceding subexpression appears at least n times, with no limit to Console.WriteLine (Regex.IsMatch str, "^[0-9]{3,}$"
        ));
        Console.WriteLine (Regex.IsMatch (str, "^q*$")); 
        #endregion//In C # determine if the login name contains special symbols: [^0-9a-za-z_]: Also cannot contain the Chinese #region shorthand expression//\d: Represents a number, equivalent to [0-9]
        Console.WriteLine (Regex.IsMatch (str, @ "^\d{3,}$"));
      \d: Non-digital  Console.WriteLine (Regex.IsMatch (str, @ "\d"));
        \s: null characters: spaces, Tab stops, NewLine Console.WriteLine (Regex.IsMatch (str, @ "\s"));
        \s: Non-whitespace character Console.WriteLine (Regex.IsMatch (str, @ "\s"));
        \w:[0-9-Z-A-Z _ Chinese] Console.WriteLine (Regex.IsMatch (str, @ "\w"));
        \w: Special Symbol Console.WriteLine (Regex.IsMatch (str, @ "\w") other than [0-9-Z-A-Z _ Chinese]);
      #endregion}//Determine if the string is the correct domestic phone number, regardless of the extension. 
      010-8888888 or 010-88888880 or 010xxxxxxx//0335-8888888 or 0335-88888888 (area code-phone number)//10086, 10010, 95595, 95599, 95588 (5 bits)
        13888888888 (11 digits) while (true) {string str = Console.ReadLine (); Do not attempt to one-step, should be one to match Console.WriteLine (Regex.IsMatch (str,@ "^\d{3,4}[-]?\d{7,8}$|^[1-9]\d{4}$|^1[3-9]\d{9}$"))
      ;
        //Verify the legality of the user entered e-mail wuhu0723@126.com while (true) {string str = Console.ReadLine (); Do not attempt to one-step, should be one to match Console.WriteLine (Regex.IsMatch (str, @ "^[0-9a-za-z_]+[@][0-9a-za-z_]+[.] [A-za-z]
      {2,5}$ "));
 }
    }
  }
}

The above is about the full content of regular expressions, I hope to help you learn.