正则表达式为英文字符，连字符和下划线

Question

I need Regex for english characters, hyphen and underscore

Example

Match :

govind-malviya
govind_malviya
govind123
govind

Not Match

govind malviya
govind.malviya
govind%malviya
腕錶生活
вкусно-же

Answer 1

try this out:

^[A-Za-z\d_-]+$

A-Za-z would allow alphabets.
\\d would allow numbers.
_ would allow underscore.
- would allow hyphen. ^ and $ represent the start and end of string respectively.

Answer 2

Try this:

(?-i)^[a-z0-9_-]+$(?#case sensitive, matches only lower a-z)

or

(?i)^[a-z0-9_-]+$(?#case insensitive, matches lower and upper letters)

sample code

try {
    Regex regexObj = new Regex("^[a-z0-9_-]+$(?#case sensitive, matches only lower a-z)", RegexOptions.Multiline);
    Match matchResults = regexObj.Match(subjectString);
    while (matchResults.Success) {
        for (int i = 1; i < matchResults.Groups.Count; i++) {
            Group groupObj = matchResults.Groups[i];
            if (groupObj.Success) {
                // matched text: groupObj.Value
                // match start: groupObj.Index
                // match length: groupObj.Length
            } 
        }
        matchResults = matchResults.NextMatch();
    } 
} catch (ArgumentException ex) {
    // Syntax error in the regular expression
}

regex anatomy

// (?-i)^[a-z0-9_-]+$(?#case sensitive, matches only lower a-z)
// 
// Options: ^ and $ match at line breaks
// 
// Match the remainder of the regex with the options: case sensitive (-i) «(?-i)»
// Assert position at the beginning of a line (at beginning of the string or after a line break character) «^»
// Match a single character present in the list below «[a-z0-9_-]+»
//    Between one and unlimited times, as many times as possible, giving back as needed (greedy) «+»
//    A character in the range between “a” and “z” «a-z»
//    A character in the range between “0” and “9” «0-9»
//    The character “_” «_»
//    The character “-” «-»
// Assert position at the end of a line (at the end of the string or before a line break character) «$»
// Comment: case sensitive, matches only lower a-z «(?#case sensitive, matches only lower a-z)»

Answer 3

[\\w-]+ this is what you need.
\\w is word character. it's the same as [a-zA-Z1-9_] which means a character from a to z or from A to Z or from 1 to 9 or underscore. So [\\w-] means a word character or a hyphen.
+ means one or more times