Only required digit can be entered

Question

I am new to javascript and I have a requirement that input field can take input of 'AND' or 123 or ().

I have tried RegExp

function requiredletter(inputtxt) { 
    var letters =/\a+\n+\d/;
    if(inputtxt.value.match(letters)) {
      alert('Your name have accepted : you can try another');
      return true;
    } else {
      alert('Please input alphabet characters only');
      return false;
   }
}

Its not reflecting the desired result.

Answer 1

I have no idea what you're asking anymore. Here is a string as whole.

let regex = /^[a-c]{3}[1-3]{3}[\)\(]{2}$/;

console.log(regex.test('abc123)(')) // true
console.log(regex.test('abc123()')) // true
console.log(regex.test('bca123()')) // true
console.log(regex.test('acb231)(')) // true
console.log(regex.test('bac213()')) // true
console.log(regex.test('cab321)(')) // true
console.log(regex.test('abcd123()')) // false

Answer 2

Use this regex:

ex = /^[a-c]{3}[1-3]{3}[()]{2}$/

const log = e => console.log(e)

const test = s => ex.test(s)

log(test('abc123()')) // true
log(test('bca132)(')) // true
log(test('abce123()')) // false
log(test('abc1234()')) // false
log(test('abc123)(')) // true
log(test('abc123(')) // false

It will return true if the prompt fits the criteria, otherwise it will return false.

Answer 3

const regex = /^(ABC|123|\(\))$/;

regex.test('ABC'); // true
regex.test('123'); // true
regex.test(123);   // true
regex.test('()');  // true

regex.test('abc'); // false
regex.text(213);   // false
regex.test(')(');  // false

Answer 4

If you want all the possible permutation of letters from abc , 123 and () , and that they are not allowed to be together, then you can use following regex:

var reg = /[abc]{3}|[123]{3}|[()]{2}/;
//This will match aaa, abc, bbb, bca, ccc, 123, 213, (), )( , etc...

https://regex101.com/r/44YoW8/2

Based on OP's comment in @Kobe's answer, (s)he wants any combination of abc , 123 and (). You can use the following regex if you just want these kind of characters, namely a, b, c, 1, 2, 3, (, and ) with any number of these letters, you can use :

/[abc123()]*/

For checking if the given string matches the regex

To test, you need to test whether the returned value of the match function is equal to the actual string. Consider following code:

test1 = "abcd";
test2 = "abc";
reg = /abc/;
if (test1 == test1.match(reg)) console.log("test1 matched"); //it won't be printed as it doesn't matches completely

if (test2 == test2.match(reg)) console.log("test2 matched"); //this would be printed.

But, if you want permutation of these letters, numbers and symbols without change in number of kind, then I don't think regex will help. See Regex permutations without repetition. But you can write a simple function for this checking easily.

Answer 5

Based on the following comment by OP I don't need any digit other than the required any input like abc,abc123,abc123(),bca,bc123,() or further will be acceptable.hope you understand my requirement now. I am adding a new answer for this question.

As far as I can understand, the OP wants to accept any permutation of the characters from the string abc123(). We can choose any number of character from this string, but we cannot repeat the characters. Therefore, everything from "a", "b", "c" to "abc", "bca", "123()", "(", ")", ")(" ... etc will be acceptable.

A regex won't work in this case because regex can't remember stuff like which characters are used and which cannot be used anymore, and hence I think following function will work for this work (might not be very efficient algorithmically):

function checkString(str){
      main_str = "abc123()";
    
      for (var i = 0; i<str.length; i++){
        chr = str[i];
        chr1 = chr; //make a copy of character
        if (chr == "(" ||  chr== ")") chr1 = "\\" + chr;
        if (main_str == "") return false;
        if (main_str.match(chr1)) main_str = main_str.replace(chr,''); //remove that character from main_str
        else return false;
      }
      return true;
    
    }
 
//Following are True
console.log(checkString("abc123()"));
console.log(checkString("abc"));
console.log(checkString("bca)("));
console.log(checkString("()"));
console.log(checkString("213"));
console.log(checkString("ab12)"));

//Following are False
console.log(checkString("abc123()a"));
console.log(checkString("abc123()()"));
console.log(checkString("abcd123()"));

What this function does is that it test whether all the characters in the given string are in the abc123() and there is no repetition of character. Therefore, abc, a, abc123() will be accepted, but not abcd, aa, or abc1233... etc.

I hope this answers your question.